You can just have a sentence or a paragraph of text. This could be fun for having some type of QR code based game where you can leave hints in QR codes.
A QR code can contain your e-mail address so someone can scan the code, see your e-mail, and then open an e-mail on their phones. If your call to action is mostly to have someone e-mail you, this would be great.
Maybe you want someone to call. Link them up to a phone number.
Don't think little of this 3-letter data type. This is where the possibilities become endless. You can use a link that takes someone to your Facebook fan page or Twitter profile. You can also link someone to a YouTube video. Or maybe you want someone to pay for something via PayPal.
QR codes can contain contact information so someone can easily scan a QR code, view your contact details, and add you on their phone. You can input your name, phone number, e-mail, address, website, memo, and more. I've commonly seen these used on business cards, for instance. You give someone a business card, they see a QR code on the back, scan it with their phone, and easily add your contact info to their phone.
QR codes can populate a text message with a number and message. You can have your QR code send you a text saying, 'Tell me more about XYZ,' for instance. This is great when paired with text message marketing
If you have an event you want to promote, you might want to stick a QR code linking someone to a Google Maps location. This will allow someone to scan your QR code and get directions so they don't have to manually type in an address. Although some may prefer to type it in, it doesn't hurt to give them another option.
Do you hate telling someone a long WEP wireless key that's a pain to type out on a mobile phone? Set it up so someone can scan a QR code and automatically configure wifi on their phones.
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