I've got Firefox and ABP as well, I don't see the ads.
But in a general sense, CLEAR advertising on FT, even the TS/S forum does makes sense. Partially because I don't think everybody clicks on every single link, anyway.
There are different usage styles on this board, IMHO. Personally, I don't click on every single link....based on the apparent topic and/or, frankly, who the OP might be. Obviously, YMMV on what individual clicks on what.
Then there's the people who come into this forum just to check on a permissible item or vent about a bad TSA experience.
Money not very well spent by CLEAR, but I don't think Randy went out and asked them "Would you like to advertise in a forum that thinks you're a rip-off?"