If you give people peer to peer software (such as a web sockets application if the peer to peer part gets implemented, but could be anything) the first step for some kinds of applications is to find a specific person and try to connect with them.  If neither of you has a URI (and knows what it is) you need a third party to handle finding each other and verifying your identities.  After that the third party isn't needed because you go peer to peer.I could of course write that third party software and put it up on a website, but then I would have to write that third party software and put it up on a website (or a server that isn't a website if that's how I want to do it).  Does anyone offer this service?  Ideally as a website and of course ideally free.
What services exist for finding someone specific to then run your own peer to peer software with?
web applications;web services
Check out GWebCache, which is an open-source spec for this sort of thing.http://www.gnucleus.com/gwebcache/And here's an open source implementation:http://code.google.com/p/cachechu/