This isn't a Google post per say, but if you haven't checked out Programmable Web, I highly recommend doing so. They catalog API's, Mashups, Howto's, and host contests.
Programmable Web has the following Google API's registered, next to them is each API's mashup count:
- Google AdSense 14
- Google AdWords 18
- Google Ajax Feeds 5
- Google Ajax Search 25
- Google Base 18
- Google Calendar 19
- Google Checkout 4
- Google Client Authentication 2
- Google Code Search 1
- Google Custom Search 0
- Google Desktop 8
- Google Documents 0
- Google Gears 0
- Google Homepage 32
- Google Maps 1128
- Google Mashup Editor 2
- Google Notebook 1
- Google Picasa 5
- Google Provisioning 0
- Google Research 0
- Google Safe Browsing 1
- Google Search 80
- Google Single SignOn 0
- Google Spreadsheets 2
- Google Talk 3
- Google Translate 0
- Google Web Authentication 1