Parsoid/Users

Wikimedia

 * VisualEditor -- Parsoid provides HTML and converts modified HTML back to wikitext on page save
 * Flow -- Parsoid provides a wikitext editor for HTML discussions
 * PDF rendering -- Parsoid provides the structured HTML input for conversions to LaTeX, PDF (both via PDF and phantomjs) and other offline formats

Gadgets

 * Google translate based new page tool for Czech -> Slovak, Google translation; the Parsoid HTML is translated and then converted back to wikitext.
 * Jackmcbarn's editProtectedHelper -- specialized template editor; Parsoid HTML is edited and converted back to wikitext

Third party tools

 * Kiwix -- Offline Wikipedia reader for smartphones, desktops etc; Parsoid provides structured HTML
 * Google knowledge graph team -- extracts semantic information from Wikipedia pages; Parsoid provides structured HTML.