Facebook's anticipated post-IPO buying frenzy has begun before the social network has even gone public.
Facebook just agreed to buy the photo-sharing app Instagram for roughly $1 billion in cash and shares.
The exit is remarkable for a startup founded in October 2010 that had just nine employees in January and has raised a total of $7.5 million.
Launched on the iOS platform for Apple devices, Instagram has grown exponentially, reportedly crossing the 25 million-user threshhold in early March. Its Android version launched last week and was downloaded 1 million times in the first 24 hours.
