That section just below the Forum Menu is a google 'Adsense' advert.
It works the same way as all google advertising and OB has no control over it and no-one logged into OB can place adverts there through OB.
There is a little tiny arrow at the top right of the advert that tells you about Adsense and how it works. Here is the link you get to if you click on that.
https://www.google.com/adsense/suppo...=ImageAd&gl=GB
The 'advertise with orchid board' bit is the section right at the top right, or in the 'Forum Sponsor' section on the left hand column. These adverts are not related to the google adverts and it is THESE ones that Marty chooses and controls. He IS selective in allowing people to advertise in that section. If you click on the 'Our Sponsors' link at the top of the screen you will see the quite short list of people who advertise there and they all have some associating with Orchid Board or with Orchid related businesses).
Marty has no control of what adds google shows in the strip under the forum menu, he has just subscribed to show a google controlled advert in that section.
Google adverts vary from person to person and from place to place. They are based on your browser history, on the words in the page you are viewing and on your location in the world. On some websites it also depends on if you are male or female and on some other details about you. That's only on sites where Google has access to that info though (like Gmail where you have entered that info and because google own the site their adverts can use it). Sites like ours don't pass that additional sort of information to Google.
The adverts you see are then based on what the advertiser told Google that they wanted to target. When people place adverts with google they can decide what keywords they want to trigger it from the web page or browser history, what location they want it shown in etc.
So what you see depends on who you are. You can actually edit the 'preferences' slightly through the link I placed above though I don't know the details of how much it lets you alter. Google also have a link on that page if you feel an advert violates their advertising policy.
But just to re-iterate. If it was in the section just below the Forum Menu then the advertisers are not controlled or chosen by Marty. They come purely from google.
I've just remembered adverts between posts as well, I think they are also google, but I don't get them as a forum supporter so I can't remember.