Pop Ups / Unders

Google's attitude to pop ups

[Bran]

I know that Google will not allow you to advertise a site on Ad Words if you use Pop ups but do they penalize the ranking of a site as well?

Also how do you initiate a pop up?

[Brett_Tabke]

No evidence to suggest that Google can or would penalize a site that uses popups outside of normal adwords restrictions.