Before I start, let me paint a scenario. You've written a very important 7-page essay for your professor, it has a major impact on your final grade. You fail this class and you'll be paying to take the same class again! You get to school and realize that you left your essay in your jump drive, no problem except.... YOU LEFT IT AT HOME!!!
Well Dropbox can fix this! Dropbox is an online service that works (How I like to describe) as a jump-drive you keep online, so you always have access to it! You install it on your computer and it will create a folder called "Dropbox" when you put a file into that folder your dropbox account online will be sync with that folder (They will be the same!). Also, if you have installed Dropbox on a another computer those folders (Including the online) will work to be exactly the same (No OS discrimination! It can be a PC, Mac, or Linux, they will be the same)!
*You can access your files from your web browser with out installing dropbox, so no need to install it on every computer you touch just to reach your files.
The Dropbox service is free, but will only give you 2 Gigs (Which is perfect for documents and small files). If you want more space you are going to have to pay, but you can get more space for free if you invite other people to join Dropbox through your account.
Lets play that scenario again, after remembering you left your essay in your jump drive (which is at home) you jump to your nearest computer, get on Internet Explorer (Chrome, Firefox, whatever) and simply download the file from your Dropbox account and print! Happy ending, hooray!
*Now you just have to remember to put the files in you drop box folder.
If you're interested in starting your own free account, the link is right here > https://www.dropbox.com/
There is also a nifty video on the page which give a great explanation of the service in case mine wasn't all too great.