Automatic content sharing
When I redesigned my web site to run primarily as a static site, with a few cgi scripts to add interactivity, I still wanted to incorporate some of the aspects of social sites I was using previously.
For example, I liked that posterous would automatically update my twitter feed when new content was posted to my old news site. Movable Type already provided atom and RSS access to my content, so I also needed to add that.
So basically, I wrote a script that would serve my static content as an atom feed — easy to do since my content was stored in MMD text and minimally marked up XHTML files. Easy enough.
Then I used twitterfeed to monitor that feed, and when it detects new articles, it adds a comment to my twitter account announcing the title and a shortened URL.
Using these methods, I simply add a new article to my site. Automatically, the Atom feed is updated, and within half an hour, an update is posted to my twitter account (@MultiMarkdown).
I am currently testing a similar setup for comments on my site (a separate Atom feed for comments has been around for a while).