Most working journalists have to deal with hundreds, if not thousands, of press releases that cross the transom every year. That's more than they're going to read, of course. And of the ones they "read," all but a few are destined to receive a half-hearted skimming, followed by a click of the delete button.
In the world of Web 2.0, some PR agencies have tried to address this issue with newfangled formats. But ultimately it's not about the format, it's about the content. And I can tell you from experience as both a reporter and a public relations consultant, there are eight ways I can usually tell that a press release is bullshit.