Imagine having a master list of your online friends, and then a little table like this:
Every time some new “add your friends” site comes along you simply walk down the table, decide who you want to connect with, listen to, or follow, and that’s that. Deciding to read their blog updates your OPML file or other subscription.
This would be so easy to build.
Update: Someone named James suggested Mugshot. Looks pretty interesting and I will check it out.