Apple, which arguably created the model for developing a modern technology ecosystem, is the leader in this field, followed in order by Dropbox, Amazon and Google. The Cloud Media Services survey looked at 2,300 connected Americans, and found that 27 percent employed either Apple's iCloud or iTunes Match. Dropbox had 17 percent, Amazon Cloud Drive 15 percent and Google Drive 10 percent. All others -- including Ultraviolet, Samsung Music Hub, OnLive, LG Cloud and Gaikai -- were 4 percent or under.

As with other new services, young people lead the way, with 20- to 24-year-olds using cloud storage the most. Music is the kind of file most often stored, with about 90 percent or more of users on Apple, Amazon or Google storing music in the cloud.

Dropbox, which is not connected to content stores as the others are, has 45 percent of its users saving music. Late last year, Dropbox bought music storage and streaming company Audiogalaxy, and it is expected to begin offering music-related features and functions.

'Key Battleground'

Music is "currently the key battleground in the war for cloud domination," said Strategy Analytics' director of digital media, Ed Barton, in a statement. To drive storage usage, for instance, he noted that Google is giving away "free storage for 20,000 songs which can be streamed to any Android device, a feature both Amazon and Apple charge annual subscriptions for."

Barton predicted that "the growth of video streaming and the desire to access content via a growing range of devices" will see increased use by services such as Ultraviolet, which is backed by Hollywood studios but currently only used by about 4 percent of those surveyed.

Except for the top four, however, the study found that brand recognition for the other services is low. However, there's a large space for growth: 55 percent of connected Americans have never used a cloud storage service.

'Device Agnostic Digital Locker'

The study also showed the continued maturation of the field. Barton said it is evolving from being simply a "value added service for digital content purchases to a feature-rich and, increasingly, device agnostic digital locker" for entertainment content.

Some of the questions raised by the study include whether consumers will be able to utilize more than one storage service at a time, and whether the category will see a basic consolidation into a few, very large providers.

Although not raised by the study, another question is whether the online storage services will continue to evolve such that storage is only their basic, most commoditized function, with differentiation coming from the new features they are in the process of adding.

A comparison could be made, for instance, to note-taking and read-later apps , such as Pocket, Amazon's Send to Kindle button, or Google's new Keep -- which have overlapping functions, but are beginning to differentiate by, say, different levels of collaboration or content organization services. In addition to music technology, for instance, Dropbox recently bought the cloud mail service Mailbox, has emphasized collaboration through Dropbox for Teams, and has been adding various photo-related functions.

Recommended Reading: Search & Destroy: Why You Can't Trust Google Inc. Synopsis: This is the other side of the Google story. In Search & Destroy, Google expert Scott Cleland, shows that the world's most powerful company is not who it pretends to be. Google pretends to be a harmless lamb, but chose a full-size model of a Tyrannosaurus Rex as its mascot. Beware the T-Rex in sheep's clothing.

Brian: