Upon clicking on "history" you will see:
- revision number (latest first)
- the date/time of each edit (UTC)
- 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 (if the editor left one)
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."
See the AboutUs weblog post Tutorial: Reading Page Histories for more info as well as the below video.
You may have noticed the new Recent Contributors feature, which is a simplified, visual/personal representation of a page's history.