Title: Have You Ever Used an Interactive PDF Application That Does More Than Fill Out Forms?+

I'm curious to learn whether anyone in the Adobe Acrobat Reader Community has ever used an interactive PDF application that does considerably more than simply fill out, sign, or print a conventional PDF form.

For example, have you encountered a PDF that can store, retrieve, update, sort, or manage multiple records directly within the document itself, without requiring an internet connection or external database?

I'm particularly interested in learning whether Reader users are aware that the free Adobe Acrobat Reader can run sophisticated interactive PDF applications when those capabilities have been built into the document.

I'd welcome hearing about your experiences or examples of interactive PDFs you've encountered.