I'm no 'puter whiz-kid but I read somewhere they can track down files you downloaded to a remote drive like a ZipDisk even if you reformat your HD afterwards. I think this was in reference to a recent case when some pervert was charged with downloading porn.
I visited a website just before Christmas trying to track down an old friend who played lead guitar in a local group back in the 60s. I found what I wanted & posted a comment about it in the Music section of this forum. I'll post a link to the thread if you wish but I don't think anyone replied to it. The next morning I received an e-mail from the webmaster of the website thanking me for my interest. He had also seen the comments I posted in the forum.