Boxes and Arrows has some nice strategies for presenting ads on a website from a page and site-wide stance - based not upon the financial success or failure of the ads, but rather from how they enhance or harm a visitor’s experience with a site.

It’s an enjoyable and informative article, well worth a look - Ads Are Here To Stay: Planning For Ad Placement.

Amongst the “Strategies” they present for displaying ads:

1. Ad Wrapping - so that visitors can distinquish between ads and the content of the page itself.

2. Clustering ads - as an alternative to wrapping, to let people know that a certain section of the layout is dedicated to advertisements.

3. Using leaderboards.

4. Using multiple layouts on different types of pages.

5. Placing an add outside of a 800×600 layout

6. Popup ads

7. Using an ad styleguide

8. Reviewing the site’s business model to see the role of ads in achieving the site’s goals.

9. The use and role of contextual ads

10. Personalization of ads.

There’s some nice discussion in the article on how each of these strategies can be implemented, and also some of their potential pitfalls.