Extension:HAWelcome

Highly Automated Welcome Tool (HAWelcome) extension automatically welcomes new users — anons and registered ones, depending on the extension's configuration — after their first edit.

The extension was originally written by Krzysztof Krzyżaniak and Maciej Błaszkowski for Wikia and subsequently forked by Jack Phoenix for ShoutWiki and by wikiHow developers for wikiHow. This page documents the ShoutWiki version, which is as of October 2017 the definitive version of the extension guaranteed to work with modern versions of MediaWiki (Wikia uses a highly customized version of MediaWiki based on 1.19 so their version does not work out-of-the-box with +, but you can check out their GitHub if you're interested in the source code of their version of HAWelcome).

Configuration
For now, refer to Wikia's "welcome tool" help page. Note that some of the features documented on the page are specific to the Wikia version.