Frank Rem from TallComponents writes about his experiences with PDF forms. Specifically, he sought to include a QR barcode on a PDF form, and to have it dynamically updated with the value of another form field. This article chronicles his trial and error efforts to accomplish this task in Acrobat.
If a PDF document has Reader Extensions enabled, then certain features that are normally only available in Adobe Acrobat are also available in the free Adobe PDF Reader. These features include saving (form) data locally and applying digital signatures. Frank Rem takes a look "under the hood" to gain a better understanding of how Reader Extensions works.