The GData APIs are a uniform interface into almost all the Google applications (Blogger, Mail, Calendar, Spreadsheets etc.). They're all based on an extended version of Atom Publishing Protocol, a REST style interface (though there is some difference of opinion on whether or not it's a best practice implementation of APP (see also some discussions on Reddit and this followup). In general this is an exciting development and I could imagine a number of practical applications for my day job, and having a unified API across all the Google Apps should make it easy to build applications which integrate with all of it.

Unfortunately, I didn't really enjoy this talk much at the time, mainly I felt there weren't enough code examples. Watching the video of the talk again now I see far more example code than I remember which indicates that I wasn't really taking it in. Most of the example code was in XML files, most of which were pretty hard to read from where I was sitting, or logs of HTTP interactions for high level descriptions of how it would work, but none of the code shown was associated with the demos in the second half of the talk. I think my expectation going into the talk was more along the lines of "here's some lines of Java code which insert an event in the calendar." Perhaps that was a little unrealistic, given the number of languages Google supply libraries for, not wanting to either show examples in several different languages or stick to one and risk alienating people, but it coloured my impressions. Though the fact that the talk was also the shortest one of the day indicates that perhaps there was room for some analysis of the code associated with the examples. Generally, unlike the previous talk, I didn't feel like I came away with enough information from this talk to dive right in and start trying stuff, so 2 out of 5. On the plus side, because this talk ended early I was able to catch the end of the KML / Google Earth talk.