There is a common misconception floating around that public relations is free. It's not- at least the good stuff anyway. The costs to public relations are just slightly hidden. Consider public relations something that is earned. In order to get your word out through the media, you have to actually be doing something relevant, interesting or worthwhile.
I'm pretty sure that most people understand and accept this.
Yet, many of these same smart people think the social web is somehow different. Going viral (for brands) is the same thing. Do something interesting, relevant or worthwhile and you're far more likely to make an impact on people, who then share it. Simply spewing new content onto the web is guaranteed not to deliver the desired result.
(Hint: this could require getting off the computer too)