It should be noted that the FAQ was largely written by a person (me) and should not necessarily be considered authoritative... if the LW community thinks something in the FAQ should change they should feel free to change it.

Some time ago I posted a poll about topics typical for LessWrong.

Anything, as long as 1) it's chosen, written, and formulated in a way that shows alignment with the values of the community, taken in a broad way; 2) doesn't make LW look bad to outsiders. (There have been cases of mods stepping in, or the community shutting down certain insistent debaters, when it came to certain discussion topics, for reasons of it being very bad PR.)

The first condition in fact could be generalizable to pretty much any human group (deviations from this norm might be taken to be, basically, trolling), and is more restrictive than it may look at a first sight. Just like in real life, apply common sense. Your message may not be technically flawed, but the success of your act of communication depends on the audience as well. People might wonder why you're telling that to them in particular. If you have lurked enough, you might already have a sense of what this community is about.

Sometimes users on LW try to establish a group discussion on topics that are not popular with most LWers, but they may be successful if people get the message that the OP values and desires the same things as them: intelligence, rationality, profound and insightful commentary, ethical behaviour and so on. Celebrity gossip, for instance, at an object level, probably cannot be adapted so that LWers receive it well, but a discussion on the role of celebrity gossip in people's lives and how it relates to populist/egalitarian status-regulating mechanisms targeted at undeservedly high status people -- that might fly.

There was just an astonishingly civil examination of the most mindkilling topic I could think of in Discussion. I've criticized people for violating the LessWrong politics taboo in the past, but I'd be happy to chat about anything from particular elections to the merits of Marxism if it was always done so painstakingly in the articles and so thoughtfully in the rebuttals.

I'm not sure how to achieve that, though. "Everybody can talk about politics carelessly" isn't any better an idea than it was before, and trying to enforce "only talk about politics carefully" might just add tone arguments without actually improving the tone.

"rationality" can be interpreted broadly enough that rational discussion of anything would count

"Rational discussion" is not rationality. You can very rationally discuss politics. You can very rationally discuss the life cycle of the cicada.

Truly "on topic" is content that helps the user to become more rational. Multiple definitions of rational apply: Being more practically effective counts. Being better able to sort through evidence counts. Meta-understanding on the meaning of rationality counts. Modelling what a rational agent might do in a given scenario counts. Figuring out what specific actions that one could take to achieve goals counts.

Anything, including politics, including cicadas, can be on topic as per the above criteria, or not, depending on context. Frowny on politics for its tendency to derail the original point. I think Lesswrong was intended as a rationality training ground.

But practically speaking, I think the votes decide, but from a standpoint of policing the boundaries this is what I'd encourage.