Not actually ads as we, the modern netizens of the internet of 2005+20 know them, but fun little sort of buttons or blinkies used to cross-promote other places on the smol web.
I've seen a few of these around. But most recently I stumbled onto navlink ads and it reminded me of the phenomenon. I know there are others out there, I just can't remember where to find them.
Anyway, I like them. It's like using the tools of advertisers to add a little irreverent fun to our indie spaces.
Ohhh like fancy signature images at the bottom of your forum comments? Yeah, I remember those really really fondly. Actually, one of the forums I was on allowed some huge ones so you could really express yourself -- I'm talking like 600x80 or something.
Yeah, there were a couple of 'basically standarised' formats, you'd put them in your signature to show people cool stuff that you care about.