QUOTE(CTphpnwb @ 7 Nov, 2009 - 01:28 PM)

What accessibility problems??
As far as I know, they can be opened on all operating systems! Heck, Mac and iPhone users don't even need to download Adobe Reader.
For disabled users - for users of assistive technologies, e.g. screen-readers etc. which struggle to make sense of PDF documents and read them in a logical way unless they're properly formatted - making a PDF accessible is an art form in itself, and most "convert to PDF" software doesn't produce PDFs in an accessible format. It can be done with semantically correctly formatted Word documents or semantic HTML for example, but it's a PITA to do (the 'best' way to do it's with the proper Adobe software, which has accessibility options built in, but you're talking serious $$$ for that), which is why I tend to avoid using PDFs on websites.