Stealth Mountain is a Twitter bot that helpfully informs other Twitterers when they mistakenly write “sneak peak,” rather than the correct term, “sneak peek.” The responses are pretty entertaining, here's a "sneak peek" of some of the good ones. More can be found if you search Stealth Mountain on Twitter.
Some people however have outsmarted the notorious constant corrector bot. I wonder how that bot feels knowing that it doesn't in fact know proper grammar.
Ian Watson smart enough to outsmart Stealth Mountain