You're thinking of 2.0...

"You're thinking of 2.0..." is a great app for magicians. After fully shuffling a deck of cards, a spectator selects a card, shows his friends, but not the magician. The card is then either hidden or placed back in the deck. The magician asks the spectator to enter their email address into a text box. The spectator then clicks on set of cards to continue... The spectator receives an email message naming the card that the spectator chose. Can also be used for mind reading.