I raised this question in the “SDMB is run at a loss” Pit thread. That’s degenerated somewhat, so I doubt many mods/ads will be stopping by, so I reask it here.
In my time here I don’t remember seeing any ads, other posters have mentioned that there used to be banners.
The Reader had determined that the miniscule revenue they got from the ads was not worth the time it took to set them up. Ad revs are 1/10th what they were in the net heyday anyway, and advertisers want a whole bunch of unique visitors to a site before they shell out $, not a few hundred visitors who load 5000 pages apiece.
It’s not that they don’t plan to sell the space – click on “Chicago Reader Online Rate Sheet” at the bottom of every page for more info – it’s that there’s little ad business to run.
And there’s also a link to the Straight Dope Store on every page as well, so you can get the books and etc.