Dropbox

Dropbox is a web-based file hosting system which was founded in 2007 by Drew Houstin and Arash Ferdowsi. It reached the millionth user mark in seven months. It created a model, which not only solves the problem of storing files, but also encourages people to become paid subscribers, and put up a video telling the story of a man losing his stuff while travelling, which made people connect to it immediately. The growth shows that solving a simple, but frustrating problem faced by people is enough to win their hearts.

The company had raised $250 million in its series B round of funding from Index Venturesm RIT Capital Partners, Valiant Capital Partners, Benchmark Capital, Goldman Sachs, Greylock Partnjers, Institutional Venture Partners, Sequoia Capital, Accel Partners, Ali and Hadi Partovi, bringing its total funds to $257 million. The company had denied $800 million acquisition by Apple and now plans to go public with an IPO in 2012.