I'm a bit wary of the idea of trying to form LW communities. Why do we want to do that?

I suspect that the problem that prevents LWers from getting things done the most is akrasia, and communities seem like one of the best tools for fighting it. It's a lot easier to get things done if you can do them together with someone.

See also the Good News of Situationist Psychology - being rational, too, is far more effective if you have people around you encouraging the habit. It's easy to slack off and fall into sloppy thought if nobody around you is serious about rationality.

Related to the above: I'm wary of setting off down a path that is likely to make LWers identify (more) strongly as being LWers.

Identifying more strongly as rationalists, however, is probably a good thing.

ETA: Graham said it himself:

There may be some things it's a net win to include in your identity. For example, being a scientist. But arguably that is more of a placeholder than an actual label—like putting NMI on a form that asks for your middle initial—because it doesn't commit you to believing anything in particular. A scientist isn't committed to believing in natural selection in the same way a bibilical literalist is committed to rejecting it. All he's committed to is following the evidence wherever it leads.

Considering yourself a scientist is equivalent to putting a sign in a cupboard saying "this cupboard must be kept empty." Yes, strictly speaking, you're putting something in the cupboard, but not in the ordinary sense.