May 24, 2011 12:01 GMT  ·  By

Dropbox has its fair share of competitors, the cloud backup/sync space is rather crowded, but the company and its product have emerged as a clear winner, at least in terms of mind share. The key is focus and a simple product that does what it's supposed to without much fuss.

The approach has been the right one, judging from the numbers the company is putting out. Dropbox continues to grow very fast, even as most people are still unaware of what a useful tool it can be.

In the past year alone, Dropbox went from 5 million users to over 25 million today. The huge growth is due to the viral nature of the service and how easy it is to start working with it.

Users can share any file or folder they've uploaded with anyone online with a simple link. Those that get the link can access the files from the web, but they can also install the desktop client, useful especially for many files or those that get updated a lot.

And once you've installed it, you're pretty much hooked, all you need to have a file uploaded and backed up on the web is to copy it in the Dropbox folder.

Users get only 2 GB of free space by default, they can get more if they get some of their friends to join, but this still adds up to a huge number of files now stored by Dropbox.

300 million files are saved each day, cofounder and CEO Drew Houston, speaking at the Startup Lessons Learned conference, said. That's 100 million more files than they did last month. 1 million files are uploaded every five minutes.

There are now more than 100 billion files saved on Dropbox, more than there are tweets on Twitter, Houston said. Of course, that doesn't mean that 100 billion files are stored on the servers, since duplicate files are only stored once no matter how many users have uploaded them.

To keep up with the growth, Dropbox has added quite a few employees in the last year as well, growing from 20 people to 55 today, half of them being engineers.