So I have a story about BsM to report for your education. One of our players has been completely inactive for about a month, and there were two other players just waiting on him silently all that time.

I just had a PM conversation with this member, it went like this:

All this time, everyone was waiting, but no one PMed anyone else or even made any comment that something was up. Let me make it clear: if someone is gone for an unusual amount of time, like a week, and there's no explanation, it's perfectly reasonable to:
1) Ask in the OOC
2) PM the player
3) Skip their character for a round without leaving them behind.
Waiting on them without saying anything is probably not going to get anything done, as they'll basically have to come back and suddenly realize that their being waited on, and that could take a long time. In the mean time, BsM and other neighborhoods have seemed near dead because of players doing this sort of thing.

This has been a public service announcement, provided by your very own Raccoon. Now get back to your roleplaying addictions. >:|

I just had to make a similar post in the RV OOC.

Which has a minimum posting rate rule, of One post per day, to prevent such posting stagnation.
Players need to take ownership of the RolePlay, or the subplot of the RolePlay, that there in, keeping it moving.
The GM's main job shouldn't be that of border collie, nipping at peoples heels to post.

See this is why I try my best to make a post in Sunset at least every time the comic updates.

I agree with the above posts. Worst case scenario, the GM would have tell the players to post, but there's nothing wrong with the players doing it. There's not much more annoying then an inactive poster whom your character is stuck with after all.