1) most of the IPs are dynamic

There is the possibility to use the hash of the client


2) not all hosts accept incoming connections

The gdf can find a common protocol !


3) it's not possible for LimeWire to determine whether your IP is dynamic or not.

see 1


4) You don't even know when a gnutella client is running on a specific host.

see 1


So i believe if you can find a unique file on the net, than you can find also a buddy.

Instant messaging is a thing the users want !