A modest proposal for X-10 Marketing:
How about limiting the popups to new members of the forum - the popups stop once a member has logged in or posted 2 or 3 times, or graduated from a one-star to a two-star member.
If that puts too drastic a crimp in your marketing plan, how about limiting the number of times any given popup will appear to a member in any one month. (Yeah, I know the marketing credo is that the more times an ad appears the more likely a sale, but still...)