I love Dropbox, it's one tool that I can't live without. From syncing to file hosting this tool is amazing. I can go on and on about Dropbox but it's better if you try it for yourself. It's free and it works.
More: https://www.dropbox.com/screencastLink: https://www.dropbox.com/
Since I use Dropbox for Totse, I will run out of space pretty soon. So, if you want to sign up, please use this link: https://www.dropbox.com/referrals/NTQ3ODY5NDc5
Once you sign up finish the tutorial and earn more storage. After that post the referral link by clicking invite more friends and then new users will use your link. In this way everyone gets more storage and a kickass tool for free.