Lewis Carroll said "If you don't know where you're going...any old road will take you there"
Let's look at some of the reasons you spend such a tremendous amount of time and effort on your blog and examine some of the metrics that you should use to measure success.
1) I write my blog because I am passionate about the topic.
Frankly, that's why most of us do it. So what's to measure? Let's face it, if you didn't want anyone else to read it then you wouldn't be publishing it online would you? So let's start by measuring the quality of individual posts.
Most analytics packages will allow you to sort by your most popular content. If you write your blog because you love it, then you may wish to set goals around maintaining or improving the quality of your posts.
Quality Metrics that I look at include:
Bounce rate is usually defined as the % of visitors that visit one page on your website an then exit the site before visiting another page. If your posts are really good, you will generally find that you have a fairly low bounce rate. People will be interested in reading other posts, about the author, etc.
Time spent on site is another quality indicator I like to review. It's been pretty well documented that people rarely read anymore. They scan. If your visitors are spending an average of 4 or more minutes on your Blog then give yourself a pat on the back! You have engaged them enough to actually spend some valuable time actually reading your post.
2) I write my blog because it positions me as an expert in my field.
Whatever your field is, blogs are a great way to increase your exposure and presence on the web. If this is your goal then some metrics that you should be using include:
Referring Sites. How people are finding you is pretty important. If you want to be positioned as an expert in your field, then getting a large proportion of your traffic from referrals sites is key.
Keywords are also important. Are you being found through Keyword Searches that are competitive for your industry? How traffic finds you can tell you a lot about what they thing about you. For example, if I were a furniture retailer I may or may not want to have a lot of my traffic coming to me under "cheap sofas".
3) I blog to make money
There is a reason that you have affiliate links and Ad Sense ads on your blog. And if you got a good offer, you'd sell it in a heart beat. This is not a criticism of people who blog for money lot's of people who are in it for the money. If this is you then you should definitely be setting 2008 goals for your blog.
For you, Quantity Metrics are most important:
RSS feeds. Many people suggest that subscribers are more important than page views or raw traffic. Or if you subscribe to Business Opportunity's Technorati valuation then you may wish to measure links.
But if you want the broadest possible market for your Blog then you need to focus on traffic. Not just the number of visitors but also growth patterns over the past 6 months. It's very simple, advertisers have been conditioned to buy eyeballs.
Whether or not this inspired you to set goals for your blog, think about this as we approach 2008:
"If you have a goal in life that takes a lot of energy, that requires a lot of work, that incurs a great deal of interest and that is a challenge to you, you will always look forward to walking up to see what the new day brings." Susan Polis Schultz