Well, perhaps - though it's possible we're thinking of entirely different discussion boards! Since there is more than one out there. The one I was referring to was fail_fandomanon on Dreamwidth.
Which is the one I was talking about, and the only one I've heard about
I long ago just gave up and accepted that I can't anon to save my life, even when posting as anonymous, because my interests are so niche. It is what it is. щ(◉Д◉щ) ("Oh, there's Yuu talking about those webcomics AGAIN....")
Well, technically, only the nonnies who know you outside of FFA can identify you. To all the others, you're just SSSS Nonny
As for niche interests... Let's just say that if I listed my three previous fandoms, you could probably identify me, because two of them are very much niches, and I'm the only intersection as far as I know :/ It doesn't get any better once you add SSSS into the mix, of course