After a little more experience, it looks to me as though the main function of Facebook is to keep me updated on what various people are doing—roughly speaking what I currently do by following other people's blogs—and to keep them updated on what I am doing. While that is worth something to me, it isn't worth very much. I'm not really interested in what most people I know casually are doing, and I'm not even interested in most of what actual friends are doing. When I get a message that actual friend X has just friended stranger Y, my immediate reaction is complete disinterest.
From which my conclusion is that it probably makes sense to keep my total number of Facebook friends small. Hopefully those whose invitations get ignored will not interpret that negatively—one reason for this post.
What I have not figured out how to do is to use Facebook as a way of getting people to either read my webbed work, of which there is a lot up, including the full text of multiple books available for free, or buy my recent self-publishing projects. My guess is that the solution is a fan page for myself, which would feed information out to interested people without absorbing much of time with the reverse stream, but so far I haven't figured out quite how to set up and control such a thing. The closest I've come is to put up some material on the "wall" of my personal page pointing at the things I think people might want to look at, and I have no idea to what extent it is actually being read.