I read a piece on this recently: http://jasonlbaptiste.com/featured-articles/how-i-pitched-te...

The main gist is that to get journalists/bloggers to write about you, you have tell them a story that they can rewrite and run. I spent years as a PR professional, and unfortunately, this is still how it works. I wouldn't say that bloggers/journalists are lazy, but they get pitched so often it's hard to select a good story for them.

Some other advice: Find out which blogger usually runs stories about Pinterest or social startups. Find out his/her email address, and write a personalized pitch. Keep it short but engaging.

Last tip: you can call Robert Scoble. His phone number is on his website, and apparently he doesn't mind getting pitched over the phone. Be sure to have your story straight, though!