The fake David Tepper was off to a great start on Twitter.
With just two innocuous tweets on Feb. 1, the billionaire hedge fund manager appeared to accumulate more than 2,000 followers. The photo looked good. The people he followed were sober financial news sources. The link went to the real Appaloosa Management website.
But then he blew it on Feb. 2 with a tweet following the Super Bowl:
The penchant for football was right, but serious Tepper observers know he bleeds black and yellow as a partial owner of the Pittsburgh Steelers.
CNBC.com confirmed with Appaloosa, Tepper's $15 billion Short Hills, N.J.-based firm, that the account is fake. But that didn't stop a flurry of new followers and excited welcome tweets.
(Read more: Big time investors as sports team owners)
The Tepper-does-Twitter fakeout raises an important question about what's real and what's not on the micro-blogging platform.
is of course the real Carl Icahn, the billionaire activist investor and chairman of Icahn Enterprises. His tweets still have the power the move a stock's price and Icahn has amassed more than 141,000 followers since first tweeting about Dell on June 20, 2013.
One giveaway that Icahn is real is the blue check symbol next to his name, meaning Twitter has verified the account as legitimate. The fake Tepper account had no such official stamp of approval.
(Read more: Icahn: 'Ludicrous' Apple board won't raise buyback)