Vague in some ways is OK, but one thing you should spell out initially is where you have to be to take advantage of this. It sounds like an in-person thing, so unless you want the majority of applicants to be disappointed after investing interest, you should clarify that participants need to be in a certain area, e.g. NY, Seattle, SF, Kansas (good luck with that one...).
The core of the outrage about Superfish is centered on the fact that it is preinstalled, that we are given no choice about its existence. In the case of PrivDog, we do have a choice to install it. Shady software will always exist, it's just that in the Superfish case it was shoved down our throats without our knowledge.