history

All edits to a page are accessible via the "history" button near the top of the page to the right of "edit wiki". Upon clicking on "history" you will see:

• revision number (latest first)
• the date/time of each edit
• who made each edit (shown as a link to a personal page for a logged-in editor or an IP address for anonymous editors*) followed by links to this editor's talk page and contributions, and
• an edit summary of what the particular edit modified.

To view a particular version of a page select a date/time, and to compare what was changed between any two edits select the two corresponding dots and click "Compare selected versions."

*Note: Edits are all made by logged-in people now.

See the AboutUs weblog post Tutorial: Reading Page Histories for more info as well as the below video.

Easy access also comes off of RecentChanges. (hist) lets you quickly view a wiki page's activity. (diff) lets you quickly see the latest individual difference in the history versions.

You may have noticed the new Recent Contributors feature, which is a simplified, visual/personal representation of a page's history.