Recently I was contacted by the creators of Cometdocs to review their product. After some poking around I found the site very intuitive.
After logging in (I used the Google login--very slick!), the screen is available for dragging and dropping files. Not only can you store files, but Comedocs has the ability to transfer files to others with a valid email address. As the sender, you can also include a message.
After selecting a file to store you can complete any of the following: create a new folder, convert the file, preview, share, and make revisions. Social networks are also accessible for quick sharing (Twitter, Facebook, and Google Plus). Cometdocs also has the option to make files public, which you can then browse if you create an account.
Cometdocs has a great blog that includes easy to follow tutorials. This site is worth a try if you like Dropbox, Box, or other online file management sites.