I've enjoyed the story very much so far, Mr. Yudkowsky.

Incidentally, and fairly off-topic, there's a "hard" sci-fi roleplaying game that uses an idea similar to the starlines in this story. It can be found here:

http://phreeow.net/wiki/tiki-index.php?page=Diaspora

Come to think of it, I have no idea if there's //anyone// with an interest in roleplaying games is this forum...if there is, have fun!