Social-networking integration. People use Facebook, blogs, etc. to connect nowadays, so make it easy for LW members to do this. E.g., users could optionally add links to FB and other social networks, and you could make it easy to share/like/+1 a post.

One FB features that would absolutely rock on LW is the ability to tag users in posts. If you think some discussion is good for MrsX, and/or you want ver opinion, it should be easy to tag another users.