Making AdSense fit your forum site

When you run a forum site, ad placement and formats are key to designing ads that will be successful but not intrusive to your regular users.

Placement: Display your ad units where repeat users will notice them

Because forum regulars tend to skip the header and go straight to the meat of the thread, placing your ad unit above or below the first post can be more effective than ads next to the logo.

Place a leaderboard immediately after the last post. This provides users who make it to the end of a thread with a 'next step' when the content ends. Try to avoid placing it after the footer, though, as your readers will likely move to the next thread without seeing the ad.

Formats: Adapting your design for multiple ad units and limited space.

Using multiple ad units, you can use a variety of formats to fill ad space throughout your site. Placing a skyscraper above the fold on the left side of your forum seems to produce slightly better performance than other positioning. However, when using multiple ad units throughout the page our horizontal bias still favors the leaderboard. Our heat map provides more details.

Use horizontal link units, which are small enough to fit near the top of your forum just below the header. For the regular forum visitor, link units offer a wider range of relevant topics to browse.

However you choose to implement your ads, keep in mind that forums are highly interactive sites with regular users. Be sure to blend the ads nicely, so they don't appear overly intrusive - but don't blend them so well they mislead your users! Every forum site is different and you know your community best, so as always use your own judgment to create the most positive experience for your users.

Tip for making the most of revenue opportunities: Like most sites, forums can benefit from opting in to image ads. Supporting image ads increases the pool of ads - particularly cost-per-thousand-impression (CPM) ads - bidding to display on your site. Since forums tend to have lower clickthrough rates than other types of sites, CPM ads can improve revenue without the need for clicks. Keep in mind, however, that CPM ads come in both text and image formats.

Source : Google.com/adsense