Getting off topic here, but I remember the SEC went full guns blazing after this kid while ignoring much bigger financial targets. The moral of the story is that you can get away with pretty much anything if you are a financial institution (in the worst case you might have to pay a small fine years later), but if you are a rinky-dink individual, look out.
Yahoo switched those stock boards to "conversations" but with no specific topics for each ticker. As mentioned Stocktwits is pretty active and the only good thing about Twitter. Not a big help finding obscure tickers unless trending.
Maybe some of these folks left after Yahoo swapped out their old message boards for this new format under "Conversations". I don't know why yahoo had to mess with a good thing. You can still find people on there making comments. Just go to yahoo finance, enter your symbol and click the "Conversations" tab to the right of "Summary". You can still find ticker specific posts but the new format sucks.