Before becoming a Dropbox user I was aware there were other cloud-storage services available, but it was the good word-of-mouth that prompted me to try Dropbox. They're a great example of how to win in a crowded market through sheer awesomeness.<p>Good timing probably also played a role, though. I went with Dropbox because sync'ing files between my desktop, laptop, and iPhone had become a huge hassle. They wouldn't be worth it to me as a USB key replacement, but as a way to manage today's proliferation of devices Dropbox is golden.