One of the primary reasons I initially set up my ThinkUp instance was to archive my Twitter history. The other primary reason was to save my Foursquare check-ins.
I'm running the old beta10 code still because I don't want to lose ThinkUp's ability to archive my Foursquare history. (Foursquare support was removed when the ThinkUp.com code got pushed to GitHub).
Anyone else interested in preserving the Foursquare functionality?