Doc Searls confirms that journalists prefer press releases on websites to be posted in HTML and not PDF or MSWord. I agree completely with him.
If you post your press releases exclusively in Adobe Acrobat (PDF) files (and you’d be amazed at how many companies do) then people can’t re-use the information (Note: there’s nothing wrong with offering PDF as well as HTML).
And as regards Microsoft Word, I personally never send press releases in Word format. There have been too many slip ups in the past thanks to the danger of hidden mark-ups.
Best practice for press releases is plain text for e-mail and HTML for websites.
Murphy's Law 