Problem
Ads are required... for business needs etc.
Solution
that lots of products are ad supported; without doing this right, the app/site will go out of business.
Should be able to hide, cancel, skip without making the mistake of clicking the ad.
Must not be confused with the content.
Must be always the same place on every screen in the app/site/process.
Variations
Um... not sure..
Interaction Details
Can click it. Should load so that it doesn't ruin the primary process.
Presentation Details
Display in boxes (background, rules)
Offset... if content is left aligned, center or right align the banner.
Do not make banners too large???
Antipatterns
Avoid saying "advertising" -- should be able to communicate this with design. If not, fix the design, don't just waste space with labels.