CJ is the largest network, they charge more to set up than other networks, they earn monthly fees outside of their cut of commissions and they welcome parasites/toolbars to their programs. I tried with them for a short time and took my little earnings and ran with them because by that time I had way too may instances of my stats not agreeing with theirs. They have had issues time and again with their ads being blocked by AV programs, most recently the popular free AVG program. When other affiliates are allowed to set a cookie in the shopping cart you stand a most limited chance of worthwhile ROI. When the merchants pushes a promo code text box at the shopper without sharing those codes you are almost guaranteed to never see a commission. It pays to carefully examine the merchant's site and their terms.