Using Internet Traffic Exchange web sites

I am using The 6 Links System because its FREE! All you have to do is look at 6 other sites for at least 15 seconds and you are then elligable to get your site in the mix. I personally KNOW it works because I spent lots of time looking at 3 of the 6 sites I had to look at just because I was interested in what I saw.

So what are credits good for if no one is buying from your website?