There are programs that tell a blogger how well their online efforts are doing. Some people love, love, love full-blown analytics and others are much more comfortable with the basics. For me, as a teacher of very fundamental online book marketing skills, keeping comfort levels and enthusiasm high with my students is paramount. An empowered student is a good student. Many creatives, and that includes writers, don't like working with numbers, but a certain level of skill in measuring efforts is important, whether checking your royalty statements, your Amazon ranking, or how many reading fans you have.
A simple free site like StatCounter can show you what you've accomplished over the last few years of blogging.
Check your blog visitor stats weekly to get a sense of how well your blog is bringing attention to your books. Are there any kinds of posts that draw more readers? Are you engaging with your fans? If you aren't in casual writing, does that translate to the success of your book sales? I'm guessing for most authors, it does.
What about you? What kind of analytics do you use to gauge the success of your blogging efforts? Is blog popularity (or any kind of popularity) important to gain book sales, do you think?