From the article:
ThinkUp, the free, open-source brainchild of programmer and Lifehacker founder Gina Trapani, keeps track of what you've done online. It extracts the data from the walled gardens that house more and more of people's digital lives then replants it in your own garden.
Need geeky skills and a server to install. Maybe they'll come out with a more user friendly version.
This solves the problem of going back into your Twitter archives and finding Tweets. For those who want the ultimate control, ThinkUp lets you export data from its own database--for example a spreadsheet of everything you've ever said on Twitter