I don't know that I'm ready to drink the cool aid on this one yet, but I am intrigued by the idea of: user, we know you're busy with a task and don't want to click through our ad, so why don't you mark the ad and view it later? The method offered by the company in This Article seems questionable, but it is interesting, and I want to think about it more. Their method is thus:

"Check ad later" pops open a daughter window containing a thumbnail version of the ad and offers other functionality, such as "add to bookmarks." This allows the user to continue with whatever she was doing when the ad appeared and to return later.