NFC (near field communication) is a wireless technology which allows for the transfer of data such as text or numbers between two NFC enabled devices. NFC tags, for example stickers or wristbands, contain small microchips with little aerials which can store a small amount of information for transfer to another NFC device, such as a mobile phone.

There's a whole set of different data types you can store on an NFC tag. The actual amount of data varies depending on the type of NFC tag used - different tags have different memory capacities. For example, you may choose to store a URL (web address) or a telephone number. A standard Ultralight nfc tag can store a URL of around 41 characters, whereas the newer NTAG203 nfc tag can store a URL of around 132 characters.

Usually, this information is stored in a specific data format (NDEF - NFC data exchange format) so that it can be reliably read by most devices and mobile phones.

NFC tags can be locked so that once data has been written, it cannot be altered. For most tags this is a one way process so once the tag is locked it cannot be unlocked.

Encoding and locking are two separate actions. NFC tags can be re-encoded numerous times until they are locked.

The easiest way at the moment is to use an NFC enabled mobile phone such as the Nexus S running Android or a newer BlackBerry or Nokia. Just download a suitable App and you can be encoding your tags in minutes.

At the moment, not very many. But that's changing and it's changing quickly. If you want to be ahead of the game then get yourself sorted with NFC now!

Here's a well maintained list of NFC enabled phones.

Like the number of NFC enabled phones, the number of NFC Apps is growing quickly. For example, you can already download Apps which will allow you to encode tags to turn your phone's wifi or bluetooth on or off - or open your favourite weather page. Encode a tag for your office desk and just tap it to change all your phone settings.

A lot of the press you see about NFC tags will be about mobile payments. It's the same technology but whereas we are talking here about using NFC to transfer a web address or simple data, NFC payments are a lot more complicated and involve a mobile wallet on your phone and all sorts of other things. While the momentum behind NFC is likely to be driven by mobile payments, the technology is capable of much more.

That's a big question and Kimtag think that the answer is probably not.

We generally feel that QR Codes and NFC tags sit alongside each other and both have their advantages and disadvantages. We think that the user experience with NFC tags is generally better and in the instances where the additional cost of using an NFC tag is less relevant to the overall cost (for example on a wristband, brochures or posters), it would be our preference.

However, QR Codes don't require the user to be so physically close, are free to print and are able to be read by most current smartphones (albeit with a suitable app).

That's the clever thing about NFC tags. They don't require batteries. They get their power from just being near a powered NFC device, for example a mobile phone.

The answer of course depends on your phone and the tag itself, but generally you need to be within a couple of centimetres (an inch).