To be fair, there are, what? 12000 people here on the boards. In a town of 12 thousand you can't possibly know everyone. Some people I form friendships with, others I only know as casual acquaintances. Some, like you, I had managed not to notice even though you've obviously been around, what with your nearly 3,000 posts.
Honestly, the easiest ways to be memorable on the boards are to either a) have a unique personality, or b) have a unique look. Having a memorable sig worked for Teflon Billy. Cyberzombie always had a cute woman in his sig. Don't get me started on Airwolf.
Posting the first storyhour worked for Piratecat. Hong makes fun of things, Diaglo raves about old school D&D, and I act the gold-digger by always trying to promote my writing with E.N. Publishing.
In more recent memory, Acquana's started doing a drawing a day, doing sketches of people's characters. There are three or four guys who post a lot on the E.N. Publishing forum who I recognize when I see their avatars, even though I don't remember their screen names off hand (I tend to be bad with names).
Also, starting threads gets a lot more attention than responding to them, or so I've noticed. So don't be depressed, please. You've got friends here, or at the very least you can get friends here with very little effort if you just ask.
Oh, and seriously, nothing endears you more to another poster than going to their storyhour or art thread and saying you like their work. I swear, I need to find me a pretty storyhour-writing girl, tell her how compelling her work is, and I'd be set. And a little evil for taking advantage of the same desire for fame I know I have.
*grin* So, Megamania, what's on your mind?