Contextual advertising works well with these sites. If you're headed for unique visitors, make your site "SE-friendly". They come mostly from search engines and are said to be "pre-qualified" clickers. So, your efforts should be directed towards keywords and keyword phrases optimization. The ideal would be to go beyond the technicalities, that is finding out what are the most searched for keywords in your area of preoccupations and try to find out why these are popular, try to find a behavioral pattern. This can be achieved by statistics and analysis.

Find out some niches in your area and the users' behavior within them ? that is, lists of searches and then see what is it customers want. This will solve your puzzle and give you exact hints towards what works best for your site. Keep in mind: unique visitors are mostly "browsers". Use ad placement and ad customization techniques that apply best for this type of users.

Sites with Regular Visitors: These are mostly forums, blogs and news sections (though news are somewhere in between). If you own sites with many bookmarks, that attract especially repeat visitors, then either you will be very imaginative in customizing your ads and finding new ways to interest your readers into clicking or if not the case, better use CPM based advertising. Brand bulding/reinforcement advertising works better in this case.

Site Theme Relates to Visitor's Mood and Purpose:

Commercial Sites: Sites selling and promoting products are more suitable for CPC advertising.By their specific, this type of site will attract visitors looking for a specific product/service/business opportunity. Thus, users are more in a buying mood, are looking for a way to spend their money profitably. These are clickers.

Content Sites, Blogs, Forums: Unless you market specific products, your readers will land on your page without the express purpose of buying something. However, you can influence your reader's mood and needs thru witty, sales-directed copywriting. You just need to know some basic things that sell. One is that people are more likely to buy from persons they know, like and trust.

So, what will help you build these? Good content and structure. Especially with content sites, these are fundamental issues to focus on (unlike commercial sites that focus more on products). Good content, professionally written and formatted for the web, containing information that is of high interest and relevance for the reader, within an easily manageable structure and good targeting on a specific theme are imperatives. On one hand these mean building confidence, the first step in selling. On the other hand they will attract well-targeted ads, more likely to interest your reader.

Great content will give you credit to your reader. Once you've gained trust, it's easy to direct your readers: you just give recommendations and the results will appear. (Avoid being too explicit in recommendations, though ? for example, directing readers towards clicking on ads is against AdSense Program Policies.)

With blogs and forums, it is a different story. Not all forums and blogs are accepted for AdSense (or even if accepted, they must be also profitable). Only genuine, specifically-themed blogs and forums, with highly interesting content are suitable.

These conditions being fulfilled, forums and blogs are perfect as a source of advertising money ? they have what is very difficult for others to achieve: reader's trust, liking and involvement.