5. Can I sign up if I am already a part of an ad network?
Yes. However, we do not permit AdWords ads to be published on web pages that also contain what could be considered competing ads. This would include all content-targeted ads as well as text-based ads. Text-based ads, for this situation, can be loosely defined as ads that mimic AdWords ads or appear to be associated with AdWords ads on your site. We do allow affiliate or limited-text links.
If you already display Google AdWords ads on your pages via an ad network, you can still join AdSense and run ads on your site through our program. However, you cannot display more than one set of AdWords ads on the same web page. This constitutes double-serving, which Google does not support.