Wouldn't it be great if you could borrow their stuff? With cloud computing, you can.

Cloud computing is all about using somebody else's stuff - their storage space, or their computing power. You might use a cloud computing service to store your home videos, or to edit your photos, or to collaborate on documents with other people.

You might use cloud computing to sync files with your mobile phone, to share the same calendar across multiple devices, or to access an important spreadsheet from any PC.

So what is the cloud? The short answer is that the cloud is the internet.

There are several key benefits to cloud computing. The first is that it's cheap - in fact, it's often free - and it often replaces traditional paid-for desktop software.

The second is that it's always up-to-date, so you don't need to worry about installing the latest software updates or security patches because the cloud computing provider does that for you.

The third is that it's reliable: if your PC crashes, your files remain safe and sound in the cloud, and most reputable services constantly backup customer data to ensure nothing can happen to it.

The fourth is that it's very, very convenient. You can access the cloud from anywhere you can get online - home, work, cybercafes, libraries, or via your tablet computer or mobile phone.

It sounds impressive, and it is - although of course there are things to consider. If something happens to your internet connection you can't access a cloud service; if the provider goes out of business or shuts the service you use, your data will disappear; free services are usually provided as-is, without guarantees or service level agreements.

We'd recommend you keep local copies of anything important, just in case, but it's important to stress that the benefits massively outweigh the relatively remote risks.

Here are five of the most common cloud computing services you're likely to encounter.

1. Post your pictures to the cloud

Cloud computing is great for sharing photos and/or videos, with services such as Windows Live Sky Drive, Flickr and Facebook offering oodles of free storage that's available 24/7 to anybody with an internet connection.

The key benefit of such services is that you can share interesting things instantly, whether that's uploading a smartphone picture of something funny or the first ever picture of your beautiful new baby, but some services offer even more: for example, Flickr includes a browser-based editing tool, Picnik, that you can use to edit, enhance or just muck about with individual pictures, and you can use geotagging to plot your pictures (or other people's pictures) on a map.

2. Open your office to the cloud

One of the best-known cloud computing services is Google Docs, which looks and works rather like Microsoft Word. Unlike Word, however, you don't need to install any software - Google Docs runs in your web browser - and the files aren't stored on your computer.

They're stored on Google's servers and can be accessed from any PC with a browser (and the right login details, of course). Browser-based documents are particularly good for collaboration, with other people's changes and comments appearing the second they've been made. If you've ever played email tennis with revision-packed Word documents, that alone will convert you to the cloud.

DECENT DOCS:Google's free Google Docs is a great alternative to traditional office software

3. Back up your stuff to the cloud

Backing up files to an external hard disk is all very well, but what happens if your computer kit is stolen or your house is hit by a meteorite? Online backup services such as Mozy stores copies of your most precious files - family photos, videos, your secret plans for world domination and so on - and stores them on its own, faraway servers. In the event of a data disaster you can then recover those files to any PC or Mac.

4. Take gaming to the cloud

Cloud computing isn't just about storing things on someone else's hard disks. Cloud computing can deliver processing power too. Imagine if you could run the latest, most demanding PC games on a cheap netbook, with someone else's computers doing all the heavy processing and simply streaming the resulting in-game action over the internet. That's exactly what OnLive does.

GAME ON:Like games but have rubbish hardware? OnLive's servers will do the processing for you

5. Sync your stuff to the cloud

Firefox 4 can share your bookmarks, browsing history, passwords and even your currently open tabs via the cloud, enabling you to pick up from where you left off on any PC you can get your hands on.

Even more usefully, DropBox uses the cloud to store your data and automatically synchronises your files with any device you wish - so you can save a file to your DropBox account and it'll automatically turn up on any Windows, Linux or Mac machine you've installed DropBox on.

You can also access your DropBox account from an iPhone, iPad, BlackBerry or Android device.

DROP IT:The excellent DropBox offers online storage and automatic synchronisation between PCs and Macs

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