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?