Dropbox: 100 million users and growing Dropbox lets you install a folder on your computing devices and then have any files you place in the folder synchronize across all of the devices; it also lets you share these files with other people. "The 100 million users milestone is more than just a number for us," says Drew Houston, co-founder and chief executive officer of Dropbox. "People start out backing up their photos, then they're sharing wedding photos with their family, and then their contractor shares the plans on a house remodel," Houston says. Since the start of 2012, the staff at Dropbox's Mission Bay headquarters has grown from 90 people to 250. The strategy has allowed Dropbox to avoid hiring tons of salespeople to sell nervous chief information officers on the wonders of cloud computing. In the coming year, Houston expects some of this to change as Dropbox looks to bulk up its sales staff and release new products that are meant to cater to businesses' security and software concerns. Microsoft, in particular, has just started its file-syncing offensive via Windows 8, which rather vigorously encourages people on PCs, tablets and smartphones to store their files in SkyDrive.