Randomly select people and order them to improve a specific wiki article. Give then +30 if they do, -30 if they refuse. Such a message is cheap, so it can work on spam economics.

This requires a single someone with authority who's job it is to imropve the LW community. This would fit into the general pattern of this person having such a job and having the power to deputize people.

I need to write a post on this general idea...

Edit: Also what manfred said. The general idea is to make it require less agency to improve LW. Either by having someone supply that agency as a service (my idea) or making the actual job require less (manfred's idea)