In the last Chapter of "A Survival Guide to Social Media" Deltina Hay outlines some different systems such as Google Analytics and Google Trends to determine the success of one's website or blog. While these ways are interesting quantitative avenues that allow you to see how statistically well your platform is being represented, I think the more exciting part of the chapter was the section where Deltina outlined the ways in which you could qualitatively examine how effectively your website is being viewed.
To me it is one thing to have your platform seen by many viewers and it is another for your platform to have a significant impact on those who take the time to visit or listen to what you have to say. However, instead of the naturally intuitive way of measuring your qualitative success, by trying to create answers out of your questions, Deltina suggests that you try to create questions out of your knowledge. This allows you to not only help you analyze what you've created by extracting solid information, but also allows you to move forward by thinking about what you can do to help improve your platform.
This is where a quantitative analysis just doesn't stack up in comparison. It can't tell you how you should go about improving your voice and your platform, only whether you need to. As a blogger it is everyone's responsibility to their audience to concern themselves with quality over quantity.