Acrobat added dynamically updated barcode fields in Acrobat 7, but they haven't been documented until now, in the upcoming PDF 2.0 specification. This article shows you how to use them to make data extraction from printed forms a lot easier.
A new feature in 2.11.25 of the PDF Library is the ability to capture handwritten signatures from an iPad, iPhone or Android tablet. Useful? Maybe not, but it is kinda neat as you can see in the video.
The PDF Library supports a large number of barcodes, including QR-Code. This article shows some tricks you can do with these dense 2D barcodes.