The EMC subsidiary, like many of its competitors, runs the gamut from consumer through enterprise backup. SMBs will want to look at MozyPro; larger organizations will move up to MozyEnterprise. The latter offers a number of administrative tools for things like user management and reporting, as well as Active Directory integration.
Mozy stakes its claim squarely in the backup arena rather than collaboration or other related areas. Mozy's "data shuttle" promises to cut down the initial backup window when dealing with larger amounts of data. From a pricing standpoint, MozyPro may best suit those SMBs with a clear understanding of how much data they have across how many machines. That's because it allows customers to specify the number of computers they want to back up and the amount of storage for each, up to 1 TB total. There's also a server backup option.