Dropbox is an amazing service. It lets you back up your files, sync them between computers, and share them with your friends.
If you have Dropbox installed on both your office and home computer, you can start working on a file in your office, save it there, come back home and start where you left at your home computer. No need to carry files in pen drive, or shuffling between various versions of same file.
Also, as it saves your files to the cloud, you can keep a back up of your important files in it. This has come handy to me numerous times, as I could get the file even in my office.
Now imagine if your computer goes blank due to some virus or hardware problem, you can still access your files on the internet or your laptop or smartphone, where Dropbox is installed.
Dropbox offers a free account with 2 GB storage. But if you sign up and install Dropbox using the link here, both of us will get 500 MB extra as bonus.
Sign up here for free 2 GB + 500 MB bonus at Dropbox