Dropbox - Online Sync and File Sharing
Paperless-Home - Find your documents when you need them most. Paperless manages them so you never have to dig through piles of paper or chaotic folders on your PC again.
Box - Box offers secure content management and collaboration for individuals, teams and businesses, enabling secure file sharing and access to your files online.
Paperless - Developers and publishers of Mac, Win, and iOS productivity, home and office and writing software such as MacGourmet, Paperless, MacJournal and many more. Based in MN.
Google Drive - Access and sync your files anywhere
Teedy - Teedy is a lightweight document management system packed with all the features you can expect from big expensive solutions but still easy to use.