Just like when Motorstorm: Arctic Edge was taken down from the PlayStation Network to counter hackers from using homebrew apps on the Vita, today, Sony has taken down Super Collapse 3 in order to do the same.
Hacker group Wololo announced via their blog that a new method of hacking the Vita was found; Less than 24 hours later the game in which said method revolved around, Super Collapse 3, was withdrawn from PSN.
Source: The Verge