I haven't done the math but from looking at sponsor stats I would guess that 95% of my sales come from the index page, 4% from the main page and 1% from the galleries. But it's very true that what works for someone else may not work for you. Experiment and see what works best for
you.
25 sites in 3 weeks is a good start but unless you're a marketing genious don'e expect ratios of 1:200. You have to send a LOT of hits to a sponsor to get sales. At least I do
