I have used several traffic exchanges for a while, because they are free. However, I found my computer struck with nasty viruses several times. 3 times now I've had to actually reset the computer to factory settings. I had a decent virus scanner, but it didn't help. I have now stopped using them for the time being, until I find a solution. Has anyone else had this problem at all? I did use them for several months with no problems but then it all went wrong.