Marc Canter's got another interesting new toy, this one something he built with some folks. The People Aggregator is basically an outliner for relationships: who I am and how to reach me, who I know and who I would like to know. This kind of listings and directory engine is of high interest to many users--the amazing traffic and number of profiles created on the AOL and AIM People Directories is proof of that.
It is going to be so interesting to see who is able to do the integration of these apps--the person who pulls it off will have a HUGE market advantage (think back to Amazon being able to get customer service right in 1998, AND have some rudimentary collaborative filtering to start to recommend books with--pulling these tools into other tools for integration and ease of use will give some lucky who-ha a strong competitive edge.