spammers are echoing your search requests and sending junk.

Quite irritating, but one can learn to recognize the junk results and mark them accordingly (or just ignore them).

A good way to learn about spam results is to make a completely bogus search terms, like "gfe7t .ogg" . The hosts that reply to that should be marked as junk.

You can also turn on your connections pane (from the view menu), and see if junk results are higher depending on the ultrapeers that show in your connections. Experiment with deleting hosts to get a sense if certain vendors and versions are mostly spammers or not. This can be a great time-waster, but it does help get a sense of revenge against vendors or versions that seem more spammy than others

If you really want to know more, the developers are trying to think of ways of identifying spammers more automatically, but I suspect the solutions will be difficult and about as effective as the fight against email spam.