Modern hard drives can hold loads of data, but the popularity of USB drives and removable hard drives shows that many people require not only storage space, but portable storage space.

It's not always practical to carry around a storage device, though, and with physical devices there comes the added risk of loss or theft. This is where online storage comes into its own, making it possible to store files and documents on a virtual hard drive and access them using a range of internet-connected devices.

Before dedicated storage services existed, web-based email accounts were used as a temporary storage medium for moving files between locations. This method is still extensively used.

The appearance of Google Mail with its associated unlimited storage space meant that it wasn't long before tools emerged that made it possible to take advantage of this space and use it as an always-available virtual drive.

Web hosting provides another means of increasing the accessibility of files, but the limited storage space offered by free accounts and the monthly transfer limits attached to many web hosting packages leaves this option wanting. Add to this the problems of configuring FTP access and it's little surprise that so many people seek a more viable alternative.

There are now numerous companies offering online storage. Some of these services are free, while others have price tags that vary according to the amount of space provided. The majority of the dedicated storage services have now adopted a subscription model, usually tiered according to the number of features offered.

Storage contenders

Services such as Microsoft's SkyDrive brought basic online storage to a mass consumer market, offering simple options such as folder sharing and image slideshows. In addition, social networking-style features such as being able to monitor the public folders of users in the same network provided a distinct home-user feel. 25GB of space is available free of charge with SkyDrive, but now there's a range of feature-rich competitors to choose from, too.

Services such as Megaupload, Rapidshare and YouSendIt all make it possible to store large files online totally free of charge. But none of these options are truly flexible, even though the likes of MediaFire do offer an image gallery option.

For anyone regularly working in two or more locations, a more robust solution is required – and this is where the new breed of online storage service comes into its own. Some have been in existence for some time while others are relative newcomers, but most have now reached the stage at which they can be considered viable options.

Simply providing online storage space is not enough. In order to stand out from the crowd, storage services need to have a whole range of extra features.

Valued added

Not all storage is free. Parting with your monthly or annual subscription fee will invariably provide access to additional storage space, but in many instances extra features are made available as well. In the case of Box, pay for a Professional or Business account and you'll be able to carry out collaborative work with more people as well as enjoy faster uploads and round-the-clock support.

Read TechRadar's Box review

Paying for an account with Humyo provides mobile access to online data in addition to automatic file backup and synchronisation, while the only difference between Dropbox and the paid-for Dropbox Pro account is that more space is provided with the commercial version.

Read TechRadar's Humyo review

Just a handful of services, like Livedrive, offer no free version at all. Services such as Dropbox, Livedrive and Humyo use desktop software to manage file transfers, sidestepping the problem of using a potentially frustrating web-based interface and making using online storage little different from using a second hard drive.

Read TechRadar's Dropbox review

This idea is treated most consistently in Livedrive, where online storage space is simply displayed as a new drive in Explorer and files can be dragged and dropped into place just as they can be with local folders. It's transparency of use that can help to make or break an online storage site.

Read TechRadar's LiveDrive review

If the boundaries between local and remote storage are sufficiently blurred, the two become virtually indistinguishable – and this is likely to be the way ahead for online storage. The more effort it takes to use a service, the less you'll be inclined to use it in the first place.

Online storage has come a long way in recent years, and the selection included in this group test shows that it's no longer necessary to settle for second best – even when just looking at the range of free products on offer. There are still improvements that could be made, but the movement towards working in the Cloud and storing data in remote locations is taking big strides.

As things continue to progress, the argument that you should ditch that USB drive and start storing files securely online grows ever stronger.

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First published in PC Plus Issue 283

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