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 favours 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.