What is a QR code, aka QBar Code? 
It is a type of two dimensional matrix code, abbreviated from Quick Response code.
Originally it was created by Toyota subsidiary Denso Wave in 1994. It became widely popular with new applications for scanning QR codes with mobile phones and smartphones.
QR codes can contain Numeric data, Alphanumeric or binary data. Along with useful data, QR code contains also error correction data that enables to restore from 7% to 30% of user data. This mechanism helps preserving data and improves reading speed and success ratio. That information can have up to 4,200 alphanumeric characters, including letters, numbers and other characters. This makes QR codes perfect for things like marketing and promotion, particularly where you have limited space, like on printed material. QR codes allow you to convey a lot of information in a tiny space.
More information on QR codes is available at Wikipedia

Static and Dynamic QR codes
Static codes once created with the information requested can be scanned many times over and over.  They are great for one item one use.  The down side is if some information needs to be changed in the QR code, it cannot be done and a new code needs to be generated. This can be a problem if many items out "there" are using the code.  This is where dynamic codes excel. Dynamic codes can be created and later their information changed.  This is a huge advantage to if a restaurant is always changing its menu.

Advantages of Dynamic Codes
Once your print items have been distributed, there’s usually no turning back. With Dynamic QR Codes, you still can make changes. These types of Codes allow you to update their content on the go and see how this impacts your campaign success.

1. Capture and measure your advertising statistics
Each time a Dynamic Code is scanned, it is recognized when, where and with what device it took place. This detailed information will help you to measure your advertising success, so you can make any necessary adjustments during an ongoing campaign.  These options are available with certain plans

2. New information - same Code
Dynamic QR Codes make it possible to change destination addresses and other Code functionality at any time without having to reprint the Codes themselves. This saves you time and money, and you can adjust your campaigns while they are running. It is possible to replace the target Web address or the document stored in the Code. In addition, you can change the function of a Dynamic Code: for example, from displaying a gallery to displaying a PDF file.

3. Correct mistakes easily
Especially with complex data such as a URL, it may often happen that you make a mistake when entering it. In the case of Static QR Code you would have to generate a completely new Code to save the correct information. Dynamic Codes, on the contrary, can be edited fast, conveniently and as often as needed.

4. More freedom in the design due to smaller Codes
The Dynamic QR Code that you print on your promotional materials does not contain the actual content you present to your users, but a short URL assigned to it. Due to this, the code is relatively simple in structure and small in size. The use of the short redirection URL also has the advantage that the Code can be scanned more quickly and thus more easily because there are fewer characters in it.

5. Plan campaigns flexibly
Your promotional materials are ready for print, but the campaign website not finished? With Dynamic Codes this is not a problem. Link the Codes to be printed to an already existing website and change the stored URL when the actual campaign landing page is completed. So you can quickly respond to the changes in the course of the project, even if the materials are already in the hands of your customers.
Dynamic Codes are as easy to generate as Static ones. If you want to know at all times how successful your campaign is and you want to respond flexibly to changes, Dynamic QR Codes are the correct tool. In order to generate Dynamic QR Codes you need special software, such as offered