Someone on Mono had written something which some people were finding offensive (although I didn't), and we weren't entirely sure whether he was joking or not. I ventured the opinion that if it was a joke it wasn't all that funny, and as soon as I'd typed that I suddenly felt as if I'd accidentally agreed with the people who said it was offensive

I know what you mean. I often find myself saying things like "Well, I didn't find it offensive, but it wasn't all that funny," when asked to venture an opinion on that kind of thing. I don't tend to be offended by jokes if they're actually funny -- though sometimes I feel guilty for laughing at them if they're sick/tasteless/etc.

I'm curious to know what the joke was now. :)

I'm afraid the joke (if joke it was - we're still not sure!) was all about the internals of the Monochrome BBS software, so if you haven't used it it wouldn't make sense to you anyway. It barely makes sense to us long-time Mono users, which was one of the reasons I thought it failed to be funny :-)