Copy combines a web interface, an iOS app, and a Mac app (as well as Linux, Android, and Windows versions) to make all of your stored documents available across any device you might have access to at any given time.
I am using Copy to make files from my Documents, Downloads, and Desktop folders on my Mac available to me anytime on my iPhone and iPad, as long as I have internet access. This has proven quite useful when I am away from my computer, on the phone with someone whilst I am out and about, and I want to refer to a document for some information. I simply pull up the Copy app on my iOS device, navigate my folder structure which mirrors that on my Mac, and download the file. The Copy app has a built-in file viewer so I can read most any sort of file. Pages, Numbers, text files, Word, Excel, PDF, images, and others are all readable within the app. For other sorts of files, the "Open in..." function allows you to send your document to other apps on your iPad or iPhone.
Among the other useful features of Copy are its Shared folder, which allows files to be shared amongst Copy users for collaboration or multiple user access, the ability to restore files from multiple previous versions (I counted at least 20 prior versions available to me when I accidentally deleted a file the other day), and significantly better pricing than Dropbox: your first 15 GB are free, compared to Dropbox, which gives you 2 GB free. Use this link, and get an extra 5 GB free after you sign up and install the Copy app on at least one device.
Whether you're looking for backup in the cloud, or file syncing across devices, Copy is a compelling new service that will give Dropbox, SkyDrive, and Google Drive a run for their money.
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