Need some advice, add subdomain to maindomain and other things

[Ramses]

Hello admins,
to describe my situation first, I'm running a forum with some addons like gallery, link directory, blog, toplist.
Since some months now my main domain www.example.com (PR3/240BL) is listed around place 450 on google, my other subdomain toplist.example.com (PR3/450BL) was listed since a long time on Place 2-3 and since some weeks it's fallen to place 440 with my main keyword.
The only change I made was adding some openx ads as I have on my main domain to the toplist. I did a search if there is a bad impact of openx ads on ranking but couldn't find anything indicating this theory.
So you may ask why did I add the ads onto the toplist if the ranking was good?
Because I wanted to give my advertisers an additional bonus and I found it not fair that the free toplist advertisers get more hits than the paid advertisers on my main page.
Now I'm thinking about moving (301) the toplist from toplist.example.com to www.example.com/toplist, this would increase my BL's at all and mabye will help to gain back a better google ranking. What do you think about this consideration? Thanks a lot for help.

[edited by: tedster at 3:56 am (utc) on Jun 15, 2010]
[edit reason] switch to example.com - it can never be owned [/edit]

[tedster]

It doesn't sound like a ranking drop because of your change - it sounds like a ranking drop because of something else that Google recently discovered about your site. You're not alone (see the June Updates thread, for example [webmasterworld.com] but it does sound more extreme and a lot like a penalty.

Subdomains no longer have any particular advantage over directories, so if you hope to pop out of the penalty situation permanently with such a move, and that's the only reason to do it, I don't think you should bother. You might start ranking for a short while, but odds are you'll be right back in the soup again after a while.

Have you been following the Mayday discussions? What you describe sounds a lot like the kind of content that Google has been hitting over the past six weeks.