As you know, some of the ads on CSS-Tricks are kind of "self managed", like the main Treehouse sponsor. I took that on because it's just a single advertiser and we have a very specific relationship and the ads are integrated into the site in a way that wouldn't be practical through an automated service. But other ads on the site are managed through an automated service: BuySellAds.
I quite like BuySellAds, because it means that advertisers can manage the ads themselves and they get inserted onto my site automatically. That means I don't have to invoice and manually update ads myself. BSA takes 25%, which is pretty substantial, but the time savings is worth it. Not to mention they likely reach advertisers that might not know about my site if not for being in the BSA directory.
There are currently three "zones" in BSA, all of which I intend to keep in pretty much their current form in the new design. The "main sidebar sponsor" will be a graphic in the sidebar we can easily make a module for. The "content sponsors" are ads that appear most often below articles or otherwise in between content. They show 2 at a time and we can also easily make a small grid of modules for those. Then there is another zone that is exclusively on demo pages, which we'll get to when we get to =).