It looks like Google does not like big ads placed above the fold. I'd really appreciate if someone could take a look at our website ( community ) : http://www.crazyengineers.com/community/ and suggest the places where we can post ads. I'm particularly interested in putting ads on the thread_view pages. I've currently placed a link unit above the breadcrumb which should take care of the hosting bills. I'm more focused on building a 'quality' site. So the longer term strategy is to list highly in Google and then attract direct advertisers.