I think most of us have experienced low eCPM with adsense on a forum. It's not a rule but it's probably the norm.

Anyway on one of my large websites we had a forum which was a small part of the website. eCPM wasn't great but the rest of the site had a decent eCPM and overall very good earnings.

One of our developers had a lot of experience with Invision, our forum software and we decided to port the rest of the site, to work within the forum and use the forum software as a CMS.

It works great and the website looks otherwise identical. However that day, eCPM and overall profits were cut in half. They never ever recovered. It's been 3 months now. The loss if thousands of dollars per month and had quite a dramatic impact on our progress.

We've been racking our brains, checking ad positions on a pixel level and they're absolutely identical. The only differences are the source code and the fact the pages are now part of invision.

We've began to wonder whether Google is detecting the forum software and smart pricing based on the assumption these pages are simply forum pages. Though that in itself would be bad, as it would mean Google is penalising forums before they've even monitored performance.

Perhaps clutching at straws, but I want to explore this a little and see if removing traces of invision will help at all.

I'm wondering whether any of you have any idea of the elements that may give away the fact its a forum software to Google. The footer did say "Powered by Invision Power Board". I've paid for copyright removal to see whether that helps.

The pages added are articles, not threads. Think of it like a wordpress blog but running through Invision.

Anything about the http headers for example that maybe giving away it's a forum software?