He's not actually on about the forum ads but the factoid slots that appear occasionally instead of ads (1 in 610 chance).
More details and full list of them here:
https://bitcointalk.org/adrotate.php?adinfo Interesting facts, funny quotes, hints, info, and ads given away to supporters.
I'm not sure if any ones have been added in a very long time.
Edit. More info:
If anyone has any suggestions for new factoids, post them here and I might add them. Factoids should be:
- Interesting, informative, or funny. The ones I wrote (most of them) are mainly focused on Bitcoin technology and history, but other Bitcoin-relevant topics could also be discussed.
- Not obvious to 99% of readers. Ideally, readers will learn something from the factoids, and maybe even be surprised.
- Not offensive
- Less than ~250 characters
- Very unobtrusive. (Much less flashy than regular forum ads.)
I probably won't add factoids that consist only of links. The factoids are supposed to be interesting in themselves. (Donators each get to choose a factoid, which explains some of the existing links and strangeness within the factoids.)