Any ideas for how to *amplify* responses to a particular site intercept?

Hello all: I'm trying to think "outside the box" for ways to amplify the survey response to intercepts on less frequently-visited Web sites. (We have some Web sites that receive millions of visits each month, and others that receive multiple orders of magnitude fewer than that.)
I'm familiar with tools such as adjusting sample display rates to lower the number of responses from a given intercept, and using quotas within an intercept to adjust responses for a given characteristics. But can anyone think of a way to increase (at least potentially) the number of responses coming from a single intercept? I'm happy to discuss this offline with anyone who has suggestions, or want some clarification. Thanks in advance!