Actually, it's not that subjective. Fundamentally you need to understand the blogger's job, which is not what you think it is. Their job, like it or not, is to contribute to page views. This could come due to sensationalist headlines, exclusives, "breaking" news, consistently high quality reporting, in depth analysis, etc. In some places, it's many of the above (eg TechCrunch), in others, it could be a very specific niche.

Now that you understand the blogger's job, you should be able to understand if your pitch is "worthy" to THEM. If it's not, DON'T pitch it, period.

The above might sound simplistic, but after running a marketing firm for four years, I can't tell you how often this advice is unknown, overlooked, or worse, ignored. Your news is "worthy" if it helps a blogger do their job, if not, it's just plain not worthy.

No matter how much you are proud of your accomplishment, if it's not interesting to the readership of an outlet, it's not interesting to the blogger, and that's that.