Yeah I think the $ has some really good ties to Stacker News, sats, and the concept of value transfer. It's actually the only symbol on the entire keyboard that denotes value, and sending/receiving value over the internet is exactly what Stacker News users do all day.

Seems like most people on here had strong negative reactions to it for its fiat connotations, but if I had to pick among the keyboard symbols, I'd choose $ too.

All things considered, my top choice would still be no symbol at all in the main menu bar with the s/subname URL structure as you mentioned for it's familiarity.