Dropbox is an interesting file hosting service which is different from other hosts in the sense that it uses cloud computing. The program also uses file synchronization across computers by means of the internet in order to share files and folders.
Dropbox is free but there is a paid option for more services. Dropbox is useful because it supports a large number OS including Windows, Mac OSX, Linux, iPhone, Android and Blackberry. This connectivity is useful for the times when you need to transfer files from your mobile devices to your laptop or vice versa. With an initial 2GB free online storage, there is also more than enough space to transfer all but the largest of files. The more people you get to sign up an account with Dropbox, the more additional space you get. I currently have almost 4GB of space.
How dropbox works is that when you drop a file into a dropbox folder, it immediately syncs it into the cloud and then with all the other systems that has access to the same folder. You can also go the website and manually upload the files there. In this way it renders emails, FTP and external transfer devices somewhat obsolete. One good thing about dropbox is that there is such a thing as revision history, which means that files deleted from the folder may be recovered from any of the other synched computers. In this way, you only handle your version of the copy and this prevents the total loss of a file. It also allows for multiple versions of the file to exist which means that editing is much easier since the changes can be tracked. Dropbox also uploads only the pieces of the file that are changed when synching.
There has been development of many apps as well, such as Gmail, BitTorrent management and synching IM logs. I believe that Dropbox can be a very useful tool especially now in this age where we have multiple systems and mobile devices and we might need to use the same files on those systems. Physical transfers are becoming a major hassle and thus Dropbox is a very good program that eliminates that need and replaces it with a better alternative.