Thanks @worldclassplayer-- in some sense, my (relatively few) Steemit posts are "selfishly motivated."

If I can post something that helps someone else "do better" or "understand," then they have a better experience here, so they are more likely to go elsewhere and say "Steemit is cool!" to other people, so the community grows... as a result of which the value of my Steem goes up...

In a sense, it's the core of a "gift economy;" our gain comes from being "of service" to others... a strange kind of self-motivated selflessness.