Justin Bieber's seal of approval on
startup app Stamped has skyrocketed it in the Apple App Store. Bieber tweeted his 26-plus-million Twitter followers and the ripple effect was contagious. However, there are many high-profile investors behind the app, which was created mainly by former Google employees. The New York Times,
Ellen DeGeneres and
Ryan Seacrest all believe in the app enough to put their money where their mouth is.
What do ...