Angus is already making Tafiti cooler. There's now a drop of the source that supports Sharepoint as a search data source. Rich Silverlight interface, the shelf functionality, web and intranet aggregation, all running in Sharepoint. And as it's shared source, you can take it, mod it, ship it, sell it, etc.

Read more about it here

http://blogs.msdn.com/angus_logan/archive/2008/01/12/tafiti-can-now-use-sharepoint-as-a-datasource.aspx