Services which provide online storage have been available for a long time, well before the term "the Cloud" came to describe any service which happens via the internet at an off-site location. Many people are familiar with uploading files for backup or for sharing, and it can be a big convenience to keep data where it is easily accessible. This is all the more true with people accessing their files and doing work on mobile devices, a trend which is not slowing down. There are some important caveats about using online document storage, though, which you may need to think about.