Statistics the key to growth

Having the right information, and being able to interpret it is the key to growing your business at any level. I am aware that traffic on five websites I manage has been growing steadily over the last month or so, and I get those statistics from Google Analytics for free. I also use Technorati to assess how much link love I am getting from other blogs.
Without these free services, I would be pretty much flying blind when it comes to assessing the impact of changes I am making on my websites.
If you register a blog with Technorati, they can tell you when people have provided a link to your blog on their blog, this blog has almost 300 unique links registered with Technorati, my other blog has nearer 500.
Google Analytics can tell you how many visitors found your blog or website, what search terms they used, and where in the world they came from. If you haven't yet got either of these up and running, now is a good time to start...