Tom Murphy asks a question, "Why is it that proponents of blogging believe that blogs must rape and pillage everything that has gone before?"
A press release can do what no other tool can do. It can alert a reporter to story he has never heard about. Whether the story is a new product announcement or an interesting case study, no other tool is so well suited to communicating the essentials in a time efficient manner. No other single tool is as effective in placing a story.