There are a lot of data points that can be meaningful for tracking blog effectiveness. That is, tracking what happens when visitors arrive at and engage with your blog content. It really comes down to the purpose of your blog. Metrics for a blog that’s focused on making a web site more search engine friendly by adding crawlable content and attracting links is quite different than a blog that’s meant to build thought leadership or brand credibility.
Many of the metrics tools used for blogs are also used for basic web site analytics. That makes sense because many blog initiatives do not have the same kind of budget as web site marketing programs do. Therefore, the analytics employed tend to be low(er) or no cost.