Carl Zimmer has published at least two ebooks, although I don't know where he found the time. That's because he seems to have made a full-time career out of studying the ebook market, the apps, the publishers, and anything else possibly related to publishing ebooks. If you are at all interested in collecting and publishing those pieces that you rescued from a defunct magazine or website, you should see what he, and co-organizer Tammy Powledge, had to say.
Their list of resources can be found here. It amounts to a semester-long course in epublishing, and you couldn't find better teachers.
If you'd like a little lighter reading, on a very...