Page Previews/zh

页面预览功能解决了用户需要打开多个窗口来理解他们正在阅读的概念或词语. 页面预览功能可以在用户浮上链接到其他文章的词语时，显示简短的主题和图片（如果有的话）. 之后，用户可以决定是否要在完成当前文章的阅读前去通篇阅读链接的那篇文章. 提供了页面预览功能的完整说明. 这篇博客文章提供了从2018年5月开始所有相关技术文档的概述.

“引用预览”功能是一个相关的项目. 每当读者悬停在脚注标记上时，它都会显示脚注的预览. 有关此功能的说明，请访问其项目页面.

简介
页面预览旨在降低探索链接的成本，并通过允许读者获得他们正在阅读的文章的上下文，或在不偏离原始主题的情况下定义不熟悉的术语、对象、事件或想法来促进学习. 对于普通读者来说，页面预览将使用户在决定是否浏览文章之前更容易获得文章的概述. 有兴趣阅读整篇文章的用户不会因为阅读不熟悉的概念而分心或气馁——他们可以简单地预览概念，而无需导航到新页面. 因此，将提高这些用户的用户体验的平滑度.

多年来，有很多人要求提供类似的功能；有一些浏览器扩展（请参阅list）和一个大量使用的小工具（更侧重于编辑器的Navigation popups）也可以解决这个问题. 页面预览于2014年首次作为测试版功能（称为Hovercards）构建，在采用率、用户反馈和对使用的影响方面，它一直是我们最受欢迎的测试版功能之一. 在Hovercards的主要谈话页面上，在两年的时间里，所有项目中的许多问题都得到了识别和解决. 在安卓应用程序上实现的移动版页面预览2015年9月，导致每页点击的链接增加了20%.

页面预览设置面板允许已注销的用户根据自己的偏好启用和禁用该功能. 登录的用户可以从“特殊:首选项”的“外观”部分启用或禁用“页面预览”. 如果同时启用导航弹出窗口和页面预览（通常，对于通过测试版功能选择加入的登录用户），则导航弹出窗口优先. 若要启用页面预览，必须禁用导航弹出窗口.



设计
对于页面预览的当前迭代，每个预览都包含以下内容：
 * 文章第一段的一部分
 * 文章中的图片（如果可用）. 图像显示为水平或垂直，具体取决于文章中链接的位置.
 * 允许用户打开和关闭页面预览的设置齿轮



与导航弹出菜单的主要区别

 * 导航弹出窗口适用于超级用户，具有许多与大多数网站用户无关的功能，例如指向元数据页面的快速链接，如历史记录、差异和用户贡献.
 * 导航弹出窗口适用于指向所有命名空间和所有Wikimedia项目的链接. 页面预览被配置为仅使用主空间链接，并且目前仅在Wikipedias上使用.
 * 页面预览的样式是为了便于阅读. 目前，Nav弹出窗口的类型大小很小，边缘很紧.
 * 页面预览对所有用户都可用，而不仅仅是已登录的用户.
 * 页面预览使用与文章类型处理一致的视觉样式
 * 页面预览强调引导图像，因此用户可以同时使用文本和图像来了解术语.
 * 小工具中的操作集感觉断章取义，因此我们需要验证其中哪些操作对读者和编辑有用.



HTML预览
自2018年3月1日起，页面预览现在以HTML形式显示预览. 这解决了许多突出的错误，提供了数学、化学和其他公式的正确表示，并确保预览显示与文章内容相同的格式.

-{zh-hans:设置; zh-hant:設定;}-
 === -{zh-hans:启用/禁用;zh-hant:开/关}-



注销的用户
注销的用户可以通过每个预览底部显示的齿轮图标关闭页面预览. 如果用户希望重新启用页面预览，可以通过任何wiki页面底部的“”链接启用. 他们还可以在浏览器中禁用JavaScript以永久关闭它.

Logged-In Users
Logged-in users can control their settings from two places. They may enable or disable Page Previews from the Appearance section of Special:Preferences. Logged-in users may also turn Page Previews off via the cog-icon displayed at the bottom of each preview.
 * If a logged-in user clicks on the settings cog, the system will redirect them to the user preferences page.
 * If a user previously had the Hovercards beta feature enabled, their preference will be kept and appear in the Appearance section of user preferences.

Success Metrics and Feature Evaluation
A number of qualitative and quantitative tests were performed to evaluate the performance of the Page Previews feature. These tests were focused on the following questions:
 * Do users enjoy Page Previews and find them useful?
 * How do Page Previews change reading behavior and do they help users be more accurate when selecting the articles they wish to read?
 * Would launching the Page Previews feature have effects on fundraising?

2015 Greek and Catalan Wikipedia test
A feature test was implemented for a period of 4 months on Greek and Catalan Wikipedias. A number of issues and bugs were reported and user satisfaction was recorded using a survey. Users had generally favorable feedback, with the majority of users finding Page previews (Hovercards) useful, easy to use, and enjoyable to use.

Read the full results of these tests.

2016 Qualitative test
To determine user attitudes towards the Page Previews feature and trace further changes in reader behavior, an unmoderated remote panel study was performed using UserZoom software. The majority of participants reported positive attitudes to the Page Previews feature. In addition, the majority of participants had no issues in turning the feature on and off. Users also described the feature in generally positive terms and reported it was not distracting to their reading experience.

Read the full results and analysis of this test.

2016 A/B tests on Hungarian, Italian, and Russian Wikipedias
To determine changes in reading behavior and evaluate the success of the Page Previews (Hovercards) beta feature, three A/B tests were launched on Hungarian, Italian, and Russian Wikipedias. The A/B test on Hungarian was launched June 7, 2016, the A/B tests on Italian and Russian were launched Sept 23, 2016.

The results of these tests indicated that Page Previews facilitate positive changes in reading behavior by increasing the precision with which users select the pages they read, reducing the cost of exploration of other pages, and allowing users to selectively focus on a single topic by providing context within a page. During the process of collecting and analysing our data we ran into a number of bugs and issues within our instrumentation that allowed us to refine and improve, to ensure subsequent tests were issue-free.

Read the full results and analysis of these tests.

2017-2018 A/B tests on English and German Wikipedias
From October to November 2017 and December 2017 to February 2018, we ran two A/B tests to gauge the performance of the feature prior to release on these projects. The results, described in more detail in the report, displayed a decrease in pageviews, but an overall increase in the number of distinct pages that readers interact with, indicating that they are more likely to explore a larger variety of topics when the feature is on. We also noted decreased usage of the back button and very low rates of disabling the feature. In addition, we ran a number of fundraising tests on enwiki.

Improvements since English Wikipedia discussion from April 2016
During the discussion from April 2016, a number of bugs, improvements, and other requests were identified which we have addressed in the following ways:

Previews “getting stuck” in the open position


 * We have since refactored our code and this is no longer an issue

Bolded text and mathematical formulas not appearing within the preview


 * Currently, previews display in HTML and content is true to the article content

A means to disable the feature from the card itself


 * Logged-in and logged-out users can now disable the feature by selecting the settings gear within the card itself.

A means to make sure page previews do not interfere with navigational popups

Providing more thorough research and A/B test results, performing a large-scale A/B test on English Wikipedia
 * Logged-in users may either have navigational popups or page previews. If you’re a navpopups user, you will not be able to enable page previews unless you turn off navpopups first, and vice versa
 * Since the discussion, we have performed two series of A/B tests, the first on Hungarian, Russian, and Italian Wikipedias. And the second on English and German Wikipedias.

Limiting performance impact


 * We have worked with our performance team to minimize any issues page previews. A dashboard with detailed information on feature performance was created.

Providing a way to enable the feature for anonymous users only


 * This is ready as well. As of March 2018, the feature is enabled by default for anonymous users on all Wikipedias except English and German

Providing data on how often users disable the feature


 * For both of our 2017/18 A/B tests, the disable rate was around 0.01%. Because the rate had been similarly low in earlier A/B tests, we also did a qualitative test to confirm that users did not have problems enabling or disabling the feature.  Our conclusion is that people know how to turn the feature off without difficulty but do so at extremely low rates.

Providing information on whether the feature was considered a nuisance


 * Based on our qualitative testing, we concluded that tested users did not find the feature distracting, or a nuisance.

Disabled pages
For security reasons, Page Previews won't be loaded on certain special pages. We refer to these pages as "disabled pages". The initial version of this can be found here:.

Future Iterations and Potential Improvements
Following the general launch of Page Previews, we are planning on iterating on the feature to add functionality. These items will include:


 * Configuration of images and other settings:
 * a number of users have requested making images configurable within Page Previews. Request declined: https://phabricator.wikimedia.org/T148995
 * other logged out preferences (more info here)
 * Article titles - currently, only the summary of the article is available within Page Previews. As an iteration, we would like to display the title of each article along with its summary
 * Reference Tooltips (phab:T67114). The project page for the Reference Previews feature has more details.

FAQ

 * Why Page Previews?
 * This is a feature intended to improve the experience for any reader who normally would have clicked on a blue link in Wikipedia because they needed an overview (definition) of that entity. It's inspired by one of the most popular gadgets, Navigation popups.


 * How do we measure Page Previews performance?
 * The theory of impact for Page Previews is that they lower the cost of exploring a link. This should mean that users are less inhibited and more focused when exploring links. We should see that the overall links clicked + (non-accidental) hovers exceed the number of links clicked without Page Previews. This is what success looks like. There are also some indications of failure that we will look for:


 * hovers can be accidental - we need to measure normal dwell time in a controlled condition to ensure that the likely rate of accidental hovers is not too high. To give an example, if a user must dwell on a link for 250 msecs before a hover shows, then we would want to make sure that there are not a large number of users who tend to dwell on a link for more than 250 msecs without clicking it.


 * Page Previews could lead to fewer page views, because the user gets the information that they need from the preview- this is not a problem, but we want to make sure that the decrease (if any) does not result in significantly less editing or fundraising.


 * the % of hovers that result in a user continuing to the page is high - this would suggest that most people wanted to go to the page anyway. If this is the case, then the hover is likely just adding an unnecessary step. We expect some significant % of click throughs for hovers. It is ~60% on Android for a similar feature, but we expect it to be lower on desktop.


 * the percentage of users who disable Page Previews is low (given that users are aware on how to disable the feature) - this suggests that users enjoy the feature.


 * Is this enabled by default for logged-in users?
 * No. If you had the feature enabled as a Beta feature you will still have the feature enabled. See Preferences>Appearance>Reading preferences to change the setting.


 * What if I have Navpops enabled by default?
 * If you have Navpops enabled, Page Previews are automatically disabled. You will have to disable Navpops in order to experience Page Previews. This is an intentional decision to ensure that Navpop users' do not have their preferences interrupted. Note: for certain browsers, you might have to clear your browser cache first for the change to take place.


 * How many options do I have in Page Previews preferences?
 * Right now, Page Previews will either be turned on or off by a user. The option to turn them off lives in each hover event. So at each hover event, a user can decide that they are no longer interested. For logged-in users, Page Previews may be re-enabled from user settings under the section titled "Appearance". For logged-out users, Page Previews may be re-enabled by selecting the "Enable Previews" link at the bottom of the page.

At the project level, administrators can determine how long a user should dwell on a link before a hover is triggered. If a project wants to be conservative, the lag can be longer. WMF will have a recommendation as to optimum dwell time that provides the best user experience while minimizing accidental hovers.


 * Why can't users just turn on Page Previews if they want them?
 * Unfortunately, there is no good way to tell users about a new feature without showing it to them first. Central notice banners have been suggested, but running them for 2 weeks would not solve the needs of future users and we do not want to run them continuously. Notifying a user of a new feature is best done using a...hover-over.


 * What impact to Page Previews have on page views?
 * According to A/B tests we did not see a large decrease in session depth across all Wikipedias. Average session depth (average number of pages viewed per session) remained relatively equal between the Previews on and off groups.


 * What about accessibility?
 * Page Previews only activate when the focus/hover state occurs over a link. They are usable for people who use keyboard navigation. For screen readers, Page Previews have proper WAI-ARIA semantics declaring them as tooltips. In short, screen reader software ignore Page Previews.


 * If I have Page Previews feedback or if I have a suggestion for making them better, where should I go?
 * Please go to the Page Previews discussion page.


 * The Page Previews continues to show an old version of a page. What can I do?
 * The Page Preview shows the cached version of a page. If the page has been edited and you want Page Previews to show the new version right away, you can purge the page.


 * How can I exclude certain page images?
 * See Extension:PageImages for details.

Code

 * Analytics and instrumentation
 * Page Previews were instrumented to measure various aspects of usage. Please see the extension page for details and feel free to ask any clarifying questions.


 * To measure content usage via Page Previews, in an aggregated way that is compatible with the existing Pageviews data, a separate instrumentation was set up that went live in April 2018. There are plans to make some of this data public for the benefit of e.g. Wikipedia editors and academic researchers.

Rollout Update July 2018
Page previews are now available on all Wikipedias. The feature is on by default for anonymous users and newly created accounts and off by default for accounts created before July 10, 2018.

Rollout Update April 2018
The next step of the rollout for English and German Wikipedias is planned for the first half of April 2018. This deployment will include turning the feature on by default for logged-out users. This will mean no changes for logged-in users. The feature will be off by default for logged-in editors, unless currently enabled. If you would like to enable it, it is available in your Preferences under “Appearance”. If you have the feature enabled already, it will stay on.

In terms of future changes for logged-in users, we have a few options we will be requesting feedback on:


 * Keep the feature off by default for logged-in users.
 * Turn the feature on by default for new accounts only. Currently, when users move from being readers to contributors and create an account, the feature will seem to vanish, and that would be confusing.  As a further step in the feature rollout, we plan to change this configuration and enable the feature for all new accounts.
 * Turn the feature on by default for existing logged-in users (Even if it were enabled for everyone, it would still be automatically suppressed for anyone who uses NAVPOPS.)

Rollout Plan
We began rolling out to Catalan, Greek, Hungarian, Italian, and Russian Wikipedias in early 2017. Data from the A/B tests represented highly favorable views of the feature. After this, we would like to continue rolling out in stages to other Wikipedias as described in the table below.

Onboarding Experience
The onboarding experience for the feature will depend on the consensus of each community on having Page Previews on by default or providing users with an onboarding experience during which they can reject the feature.