The practice of grazing through the website Wikipedia, having drifted away from the article you were originally reading. Leads to people developing an in-depth knowledge of obscure subjects, and can go unchecked for hours. It often stems from hitting the "Random Article" link on the nav bar
"Ah shit! I was supposed to pick up Timmy from Boy Scouts, but I was wikigrazing! Oh well, at least I'll be able to tell him about Heinkel jet engines....."