Post a notice
Anything the scene would actually use. Gear you're selling or hunting, someone you need in a room with you, a question you're tired of googling, or something you should have said at 2am.
Nothing publishes itself. Every notice is read by a person and typed onto the board by hand, which is slower than a form that posts straight through and is the reason this page isn't full of ticket scalpers. Expect a day or two.
A name, an alias, or nothing at all — same as everywhere else here. How someone reaches you is a separate choice, and the two fields at the bottom explain themselves.