I recently wrote a short post outlining my thoughts on the distinction between open data (the term generally associated with the behaviour of governments and other public bodies providing declarative and programmatic access to various data sets) and transparency (the behaviour of governments publishing honest accounts of their behaviour without restriction).
In reviewing a few of the open data sets that BuzzData linked to on their recent post about these open data portals, I noticed that some of the data is provided in formats such as PDF. While it may be transparent to publish data in this format (PDF is a document format with reasonably high market penetration) the data that they contain is obscured by the purposes of the document encoding. PDF is designed to make documents look good, not to separate out the content abstractly from the format. Consequently, the data - while being distributed for human consumption in an accessible manner - is not open in the sense of being in a declarative or programmatically accessible representation.