the problem with trying to analyze too deep into the conversions - other than discovering a real problem like a bad link code is that there are so many outside influences - is it winter, college time, middle of summer, whats the mood of your target surfers, are you targetting the right niche for the traffic youre getting...even inside a sponsor Ive seen them have really good conversions on one site and shit on another - way too many variables - I think if I got to 10K hits to a sponsor with LL traffic and didnt see any signups Id start looking a little harder from both ends
