My mistake - but it does allow you to type in a number files that have to be shared before you are not considered a freeloader. If you are really freaked by the thought someone might "steal" from you set it to a couple of hundred

Then sweat over your uploads list, every time someone had the audacity to try to get a file off you, search the IP address that shows up and then kill em if they dont have what you consider to be a reasonable "share portfolio"

Or you could just take it easy and share what you are comfortable with sharing, knowing you are doing the right thing by other users, and not get an ulcer over something you can not control.