Copy.com is Giving away 15GB of free online storage space, But you can get 22GB. They have a referral offer where everyone you refer gives you 5GB extra as well as the person your refer, plus 2GB extra for twitting.
So what you need to do
Go through the referral link here
Sign up with your name and a usable email id.
Click on the verify Email link in your inbox and download their App. (Yes you have to)
Ensure you Download the copy.com App else you will not get the extra 5GB.
Once the App is installed check your account, the extra 5GB should have been added to your account.
You will also get a auto-popup to tweet about copy.com, just tweet the same and get 2 Gb more.
If you have any issues you can contact their support team email@example.com
You can invite your family or friends to create accounts and get more storage.
Many people have added upto 2.1TB yes that's right. If you have a website and wanna save on Backup costs then you should definitely use this option.
I am currently checking out the speed of uploads and downloads. If you have any updates or other tricks do update me in the comments
The images are not mine and are found on the net