(# Edit: It is available only for two years and has been discontinued since.)
But using it along with my Yahoo mail makes it simply awesome. All my important communications like my Insurance Premiums, Bill alerts etc generally come to my inbox and all I have to do is to download it into the Dropbox and it is available to all my devices/computers including my Samsung/Blackberry etc. There have been more than one occasion when Dropbox has come to my rescue.
At one occasion, I needed a photo for a property related issue, and I was not carrying one. I just pulled it out of the Dropbox, and it save a big deal. Hence, productive.
On another occasion my wife forgot to carry her Photo ID proof while travelling on a flight. Dropbox came to my rescue there too.
I had gone to the bank regarding my home loan, inspite of all documents, they wanted to see a particular file reference. Fortunately, I had just made a copy of all important documents and kept it in the Dropbox. And I was able to pull it out and show it to the bank officials, saving me a full trip and a day.