Maybe some anti P2P company is bombing the network. Right now I
am seeing a lot of UDP traffic coming out of the 69.85.242.x range
today, so you might find some relief by blocking that /24. I'll give
you a list of ranges to block in your firewall tonight when I get back
home. That'll take some of the load off of BearShare. ;]

There have been no configuration changes in BearShare for a while
but I think you were offline at the time so you wouldn't have noticed
until now. The last change restricted pongs to reporting only the
nodes using the ports 6346 and 6348. Not much of a change but
you might find it worth trying either those ports or something else,
depending on which port you are on right now.