Anyone use interstitial ads?

I was wondering if anyone used interstitial ads?

Is there any good ones for WordPress?

Has anyone had any issues serps wise? I know Forbes and Webpronews use them. I can't imagine that it has much of an impact, but then again, they have huge authority.

I am thinking about using them. Any insight, would be appreciated.

I remember years ago, AdBrite had interstitial ads you could use. I'm sure there is a plugin to integrate them with Wordpress.

I can't say for sure that they impact SERPs, but it can't be good, with Google hating all forms of monetization and whatnot. I bet that giant ad splashed across the screen would be considered a "bad user experience" or something.