Funny is fine, just skip it when it involves haranguing, smearing or ridiculing specific politicians, ideologies or religions.
Odds are you'll screw up a few times on hacker community forums -- in ways detailed in this article, or similar. And you'll be told exactly how you screwed up, possibly with colourful asides. In public.
When this happens, the worst thing you can do is whine about the experience, claim to have been verbally assaulted, demand apologies, scream, hold your breath, threaten lawsuits, complain to people's employers, leave the toilet seat up, etc. Instead, here's what you do:
Get over it. It's normal. In fact, it's healthy and appropriate.
Community standards do not maintain themselves: They're maintained by people actively applying them, visibly, in public. Don't whine that all criticism should have been conveyed via private e-mail: That's not how it works. Nor is it useful to insist you've been personally insulted when someone comments that one of your claims was wrong, or that his views differ. Those are loser attitudes.
There have been hacker forums where, out of some misguided sense of hyper-courtesy, participants are banned from posting any fault-finding with another's posts, and told "Don't say anything if you're unwilling to help the user." The resulting departure of clueful participants to elsewhere causes them to descend into meaningless babble and become useless as technical forums.
Exaggeratedly "friendly" (in that fashion) or useful: Pick one.
http://www.theonion.com/content/node/29225
...remember 1999? Remember how everything was new and fresh and had E- attached to its name? Unlike now where the 'e' is droppd?