ParticipateDB

From the about page: OpenComment is developed and supported by Urban Insight, a leading technology consulting firm with deep roots in the field of public participation and urban planning. […] Many planning documents, like comprehensive plans, specific plans, EIRs and zoning codes are created in PDF format to make it easy to review the documents. However, enabling a large number of people to elegantly add comments to a PDF document has always been hard. Our solution is OpenComment. Just click to comment. You can read the launch announcement here: How Do You Collect Comments on a PDF on the Web?