These sort of editors make an edit and then realize they didn't do what they wanted to, that they could have put something better, or that there's something more to be said. note So they make another edit. And another, and another, and another, until it's finally perfect — or the server breaks, or sanity is lost, whichever comes first.
While preferable to leaving mistakes uncorrected, this type of edit fills up the page history with garbage edits, which often becomes annoying. We have a Preview feature — you can test most of your markupnote before saving your edit, so be sure to do so. You can also play around with different kinds of markup in the Wiki Sandbox.
In fora, this often produces an ominous, suspicious looking "post edited by author on ??/??/???? ??:??:??" message. This site's forum has a preview functionality as well as a sandbox forum for correctly typing spotless markup-heavy posts.