Dropbox is a file hosting service operated by Dropbox, Inc., headquartered in San Francisco, California, that offers cloud storage, file synchronization, personal cloud, and client software. Dropbox allows users to create a special folder on their computers, which Dropbox then synchronizes so that it appears to be the same folder regardless of which computer is used to view it. Files placed in this folder are also accessible via the Dropbox website and mobile apps. Dropbox was founded in 2007 by Drew Houston and Arash Ferdowsi, as a Y Combinator startup company. Dropbox provides client software for Microsoft Windows, Mac OS X, Linux, Android, iOS, BlackBerry OS and web browsers, as well as unofficial ports to Symbian, Windows Phone, and MeeGo.