Well before we delve into this it may be useful to take a step back and explain what cloud computing is… Cloud computing is “the practice of using a network of remote servers hosted on the Internet to store, manage, and process data, rather than a local server or a personal computer.”
Rather than have the files physically on the computer / laptop in front of you they are being stored in the sky above you! Well you know what I mean but at least it makes more sense why it’s called the cloud!
One drive (previously SkyDrive, Windows Live SkyDrive, and Windows Live Folders) is a file hosting service that allows users to sync files and later access them from a web browser or mobile device
Dropbox is a personal cloud storage service (sometimes referred to as an online backup service) that is frequently used for file sharing and collaboration.
Both in essence are very similar and offer free plans for light users. While Dropbox currently offers 2GB One drive recently increased its to 15GB however Dropbox feels more user friendly and has a lot of third party tools too. Dropbox is also said to have the better security system.
Google drive is similar to One drive and if you have a Gmail account you will already have access to this!
Obviously there is a huge amount of information about cloud computing below are a couple of articles to get started with.