A Reddit style API so people can write bots for Lesswrong or do some extention themselves. Consider having a pool to reward programmers that implement certain features in this comment thread.
LW runs on Reddit source code. I think this would probably mean to update it to a newer version of that code base.
I think it'd be a good idea to keep a list of the ways we'd like to see LessWrong improve, sorted by popularity. Ie. email alerts for new responses.
So if you have an idea for how LessWrong could be better, post it in the comments. As people up/downvote, we'll get a sense for what the consensus opinions are.
I think there's a pretty good amount to be gained by improving LessWrong.
Note: I say "ways to improve" instead of "features" because "ways to improve" is more general.