Someone who emphatically corrects others spelling errors in a public arena such as in a chat room or discussion board. The typo nazi then abruptly leaves the conversation with a dismissive and unbelieving attitude about the misspelled conversation.
Today a tech giant made splahing news comments regarding it's new lineup of gadgets. Notice the missing "S" in splashing.
Reply: Typo Nazi
The author of this article is dumb. This article isn't even spelled right! Bah why should I even read it.