WordPress 3.2 introduced an update to the automatic updates built into WordPress (you know, the functionality that lets you click one button and update your install) to allow for partial downloads. This meant that when automatically updating your WordPress site, after 3.2, only a partial download (of changes) would be necessary, and not a full copy.
According to Napkin MathTM by core developer and Audrey Capital Tech Ninja Andrew Nacin, shipping 3.2.1 (the update that came right after 3.2) as partial builds saved WordPress.org approximately one terabyte in bandwidth costs compared to the previous full download upgrades. Additional savings are expected in later versions as well, since a lot of people upgraded to 3.2.1 from 3.1 instead of 3.2.
This was one aspect of the move to partial downloads that I hadn’t really considered. Had you considered this benefit when you first found out about partial download upgrades?