I recently had a similar situation happen to me. I was looking for a audio file & got a search result that matched my search description, but instead of a mp3 file, it was a zip file. I made the mistake of unzipping & opening it ( after doing a virus scan ). It unzipped into 2 files ( one of the files was named "open me first" )
, & the other "I believe" was named _x-finder.exe . If you see these files, don't open them, DELETE THEM!!! Although they are not seen as viruses, they will install a program that takes you out to porn sites & will seemingly register your e-mail account with these sites.

I'm not going to get into the right or wrong of file sharing. People have been copying songs as far back as I can remember.

This zip file was obviously planted to discourage file sharing, but I'm still on LimeWire.