I mostly quit contributing because of the deletionists, but I have some recollection about one of the "alienated" communities the article mentions. For a while there was a concerted attempt by multiple webcomic authors to insert references to their webcomic in seemingly as many articles as possible. So you would get edits for example to the ISS: "$CRAPPY_WEBCOMIC mentioned the International Space Station on January 8, 2007 when $WEBCOMIC_CHARACTER bought a telescope and $IRRELEVANT_TEXT". While I didn't care that much if every webcomic got an article, they were basically using Wikipedia as advertising and would get into fights when you tried to make it not advertising. After a while you start identifying "problem communities" and start treating those contributions less charitably.