A user's watchlist allows tracking changes, similar to the "Recent changes" display, but for changes to a set of specific "watched" pages. Click the "Watchlist" link in the user menu, to access the currently logged in user's watchlist.
Typically, a user will watch pages related to their interest areas, or after an edit to a page, to see if there are any follow-up edits.
The watchlist will be empty at first, add pages by navigating to a page, and clicking the "Watch" link in the more menu at the top of the page. There is also a "Watch this page" tickbox provided when committing changes to the wiki, so that a user may easily watch for changes to pages that they have contributed to.
The watchlist feature can be particularly useful on a busy wiki where the "Recent changes" list can be long. A setting on the prefierences page will allow the user to be notified by email when there are changes to pages on their watchlist.
On the watchlist display, some page names appear in bold, to indicate whether the user has already seen a change by visiting a page, or not - a bit like read/unread emails in an email inbox. On the "Recent changes" page, bold highlighting indicates pages currently on the user's watchlist.
There is a tab dedicated to watch list settings on the user preferences page.