They have also been around since 2003. They never once went bankrupt before going public and it is doubtful they will start now.
People seem to think that this is bubble 2.0 (more like grasping at straws), but this is no where near the same situation. Lessons were learned and implemented from those mistakes. LNKD is one of the prime examples of a company that learned from the DOT-COM bust and improved themselves. The internet has significantly changed since 2001 and if you can't see that, then you shouldn't be in any tech play.