Adobe has a put out a video inviting users to share they stories about what they like about Acrobat. It is organised by Lori Defurio who has spent many years promoting Acrobat and patiently taking flack from users and developers. I’ve met her at several conferences and she is a great evangelist for Acrobat and public face for Adobe. She knows Acrobat is great detail (and also knows who to contact if you want very specific knowledge).
So if you have any interesting and novel uses for Acrobat (which is a pretty flexible tool), have a look at http://tv.adobe.com/watch/loris-corner/share-your-acrobat-story/. And if you have any gripes or suggestions for Acrobat, she is also a good starting point.
IDRsolutions develop a Java PDF library, a PDF forms to HTML5 converter, a PDF to HTML5 or SVG converter and a Java Image Library that doubles as an ImageIO replacement. On the blog our team post about anything interesting they learn about.