Mar 22, 2011 12:30 GMT  ·  By

Dropbox is a great file-sharing service that anyone who's ever been in need of one has stumbled upon and likely loved. Not for lack of competition, Dropbox has continued to add plenty of new users in the four years it's been around and is now said to be on track to be making $100 million in revenue in 2011. Not bad for a company that only raised little over $7 million since launch.

In fact, while everyone is fixated on the likes of Groupon, Zynga and Twitter, Dropbox may very well be worth $1 billion to $2 billion and analysts say it may be a hot target for acquisition for a web giant, the likes of Google.

Dropbox is a file sharing service which aims to make it easy to sync a file across multiple computers or share it with friends or coworkers. There are plenty of file-sharing services out there, where Dropbox shines is in its simplicity and word of mouth marketing.

With Dropbox running on your computer, any file copied to a dedicated share folder will be uploaded to the Dropbox cloud. It will then be available to any other computer you have linked to your account, as well as to any mobile device with a Dropbox app installed.

Of course, there is also a web interface if you need access to your files while you're using another computer. That's just part of the equation, the other is easy sharing with other Dropbox users or anyone you allow access to a file.

By default, you get 2GB of free storage. You can get more by getting friends to install Dropbox, 250 MB for each one. But if you're serious about cloud sync, you need to pony up for paid storage. $9.99 a month will get you a 50 GB piece of the Dropbox cloud.

This is how Dropbox makes money and the strategy seems to be working. Revenue for 2010 was already equal to Dropbox's own estimates for 2011 and it has been growing at a rate of 10 times per year. Some estimates put Dropbox revenue at $100 million this year.