It's the end of the year, and you need to back up your files. You don't want to burn CDs or DVDs. You want to have easy access to the files at home or on your iPad or phone. You don't have a USB Flash drive handy. What do you do?
I would suggest getting an account on one of these 5 services. They provide easy access and secure storage of your files. They have applications to allow you to easily move files from your desktop computer to online storage to your laptop or mobile device. Most of these services will give you around 5 GB of free storage, which is enough for the average user. People run into storage size issues if they save a lot of videos and pictures, but for word processing files, and spreadsheets, and databases, this seems to be plenty.
These services also allow you to purchase more storage, if needed, but usually their free amount is enough. Here are the ones that I have used and found easy.