Mega is the name of a global file-sharing / storage service.
Mega's official launch is due in January 2013. It is widely reported as a resurrection of the MegaUpload file locker service that was shut down by U.S. authorities in January 2012, but in reality, Mega is significantly different to that predecessor.
Mega was announced in October 2012 by Kim Dotcom, the German-born New Zealand resident who had also founded MegaUpload, and is (at time of writing) the subject of an extradition battle at the request of U.S. authorities.
The service welcomes partners from all over the world, except the United States. Dotcom stated that this was just one factor in Mega's "raid proof" strategy.
All files stored by the Mega service are automatically encrypted, and the key is available only to the uploader and the people he/she decides to share it with. Even Mega server operators do not have the decryption key to check the contents of files. Encryption cannot be disabled by an uploader.
Mega puts responsibility for uploaded files squarely on the user uploading them, and also leaves the responsibility for fighting copyright infringement to copyright holders.
Mega is the subject of controversy as the case over MegaUpload is still online as of October, 2012.