Blogger outreach and PR is difficult - I've read a lot of How to articles and guides that say stuff like "Get bloggers to review your site or product", or, "Get as many backlinks from other bloggers as possible".
So everyone knows what to do, but no-one's talking about how to do it. In fact, gathering backlinks is often time consuming, ineffective and infuriating.
Hands up anyone who has spent several hours emailing other bloggers asking them to take a second to look over your new [blog/site/product/service/article/video] and gotten almost no response. It happens all the time.