Umm ... I know I'm not alone on this, but mashups via Open Social are very cool. Trying to use Google apps and hoping that's a good place to create some mashups for business. I'm also in an beta mashup-app-building tool.
What's amazing about OpenSocial is how it accelerates the pace of interconnection, previously rampant mostly within single, rapidly growing social networking communities. OpenSocial ties these fast growing communities together for a quantum leap in value and connection (to people, groups, organizations, philanthropic causes, etc.) Blogging, tagging, media (video and picture) sharing, and online personal or professional communities have become interconnected. Browser technology, such as from Flock, add to the usefulness of these ever-more useful tools.