Data de-duplication can reduce the amount of storage capacity an enterprise requires by as much as two thirds, said ESG's Whitehouse. It has been available before, but this year companies started to integrate it with storage arrays or sell it in appliances, bringing the technology closer to a turnkey solution, she said. They also established data de-duplication as a technology customers could trust, at least for archived material.

"If you eliminate a block of data that somehow negates the value of that data when you recover it ... that's a really scary prospect for some companies," Whitehouse said.

So far, most enterprises are only using it for secondary storage, or the archived information that's backed up for safekeeping, she said. The next step will be to embrace de-duplication for primary storage, the data that applications are using in real time. Users will start to trust the technology enough for that next year, she said. In July, NetApp enhanced its V-Series storage virtualization products so they can perform de-duplication on primary storage systems from third parties such as EMC, Hitachi and HP.

3. EMC-Pi

In late February, enterprise storage giant EMC bought Pi, a provider of software and online services for consumers to keep track of personal information stored locally or online. The deal, which followed the company's 2007 buyout of online backup provider Mozy, was one sign of growing interest in cloud storage.