Maybe I have been thinking about the killer application the wrong way.

Consider this Jeff Croft’s lifestream:

To borrow a phrase I first heard from the Scobelizer, its like a river of data. Most recent activity at the top and then the rest in a descending list.

What we really need is a service that allows an individual to create their lifestream. Add the important part missing from Jeff Croft’s life stream, RSS.

Update:  Jeff Croft’s lifestream does have an RSS feed. (link)

So you have a service that will let you collect your life stream data into one space. For instance, I use del.icio.us for bookmarks, Flickr for photo’s, and Wordpress for blogging. I would add those three services into my lifestream.

You can send your lifestream out for friends to subscribe to. Since its formatted as RSS, they can import it into any reader the like. If they want a little more value added then you provide an interface similar to Spokeo for ingesting the lifestreams and aggregating them together.

Simplicity with value added services is what people want.