most mlients (for example LimeWire, I am not sure about Bearshare) still have the original Gnutella 0.56 "Discovered Hosts" feature implemented, which means that while you are a part of the GNet your servent catches IP adresses of other users. When you disconnect and try to connect again, all these Discovered IPs will be tried to connect to, and, as a matter of fact, it works - there will be enough of them who are still or again online. Indeed, I sometimes get connected faster and to a greater amount of hosts when deactivating the AutoConnect servers and trust to Discovered Hosts only. But of course this method is likely to fail if you were not connected to the net for a long time (i mean weeks, months) and your IPs are out of date.