Originally Posted by wallcraft
As noted by tomsem, Amazon is using Adobe Reader Mobile 9 to render PDFs on the DX. This capability could be added to the Kindle 2 as well, but on the DX Amazon is not using the reflow capabilities of ADE for PDFs which would be needed (or be helpful) on a 6" screen. So it would take a bit of work to add PDFs to the Kindle 2. Amazon does have an alternative reflow method - send your PDF to them for conversion to MOBI.
One interesting property of ADE that the DX uses, but which is a much requested upgrade for the Sony Readers, is the clipping of PDF margins. The DX does this by default, but the Sony Reader's portrait mode leaves the margins intact (I'm not sure about their landscape mode). This means that Bookeen and other new ADE licensees have no excuses for leaving the margins unclipped.
My comment was a one line comment and apparently not very clear. The original poster basically asked if Amazon could provide a PDF viewer for the Kindle 2 with a software update or if there was a hardware requirement for the PDF functionality. Here's a more indepth answer that I hope will clear up any confusion.
The PDF viewer functionality is provided by software so technically it is possible for Amazon to provide a PDF viewer for the Kindle 2 (and Kindle 1 as well). However, the Kindle 2 only has a 6" screen, which is just slightly larger than a 3″ x 5″ index card, and from a practicle matter this sized screen is just too small for displaying many PDFs. A large number of PDFs are based on 8 1/2" x 11" pages. The new Kindle DX can display this page in portrait mode by removing margins from the PDF and by scaling down the page slightly and still have an acceptable page that can still be read. The Kindle DX can also be turned sideways and essentially display half of a full-sized 8 1/2" x 11" page, and clicking the Next Page button will display the next half. None of this is really possible with the small screen size used in the Kindle 2. Shrinking a PDF page would result in text too small to read. Dividing a full 8 1/2" x 11" page into sections would require cutting it into at least fourths. So a PDF viewer on the Kindle 2 just isn't likely from a practical standpoint.
[Edit: I hope none of this sounded disrespectful to Wallcraft because that's definately not the intention.]