They used a javascript applet for signups and voting. Signups were limited to either 10,15,or 20 players, with either two, three, or four mafia. There were usually only three roles: mafia, town, and one cop. Mods occasionally added other roles, usually in flavor heavy games, but since the only actual way to remove people from the game was to lynch them or for the wolves to eat them, there were no killing roles like vig or sk. Also, the cop had to vote to use his inspect, so at the beginning of every round that the cop still lived, everybody randomly voted to hide the cop. Since the only way to end the game was for all the wolves or all the humans to die, alternate wincons were not a thing. The mods were more involved in the game, and it wasn't uncommon for them to give hints. Everything else worked pretty much the same as here.
I'm not entirely sure, but what you're describing pretty much sounds like the internet version of IRL mafia. It's obviously not my call, but I would strongly recommend playing one beginner's/"normal" game before joining a bastard one, as bastard games tend to have a lot of stuff going on — too much stuff, if you're not used to forum mafia.
I'll throw something onto Elephant's commentary: If you are going to play a bastard mod without prior experience of even basic mafia of the Bay 12 kind, I recommend you read over a previous bastard game. I've included three bastard game links in this post for you to look over.
Kill Your Own Shakerag Now was on the extreme end of the scale. Though definitely bastard, it will probably be nothing like this game. It's still a fun read, though.
Politibastard was a bit less extreme. Politics. Just... politics. In any case: it's closer to the kind of bastard you should expect from this game.
And finally...
Bellsounder, which I imagine is the closest in bastardness to this game.