If you want to keep track of visitors to your blog, you’ll probably be interested in the WordPress.com Stats plugin.
Set up for stats
Download and install the plugin. Then go to WordPress.com and sign up for a username. Check your email for the API key.
Now go back to your blog’s Dashboard, click on the Plugins link and then the WordPress.com Stats link. Enter your API key.
After giving the plugin some time to collect stats — a day or two, or maybe a week if your blog doesn’t have many visitors, log in to your blog’s Dashboard and click on the Blog Stats link.
Got an error?
At this point you may be taken directly to your stats or you may see a login page.
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At worst, you may see an error message. This happens to me because I look after blogs for others and have several WordPress.com usernames. In that case go to WordPress.com and log out. Then try the Blog Stats link in your blog’s Dashboard again.
Log in to the stats if necessary
Now comes the confusing part: log in with your WordPress.com username and password, not your blog’s username and password.
Now try that Blog Stats link again.
View the stats
If you don’t have the ‘multiple personality’ problems that I face you were probably able to just click on the stats link and see your stats. Over time these build up to be incredibly useful. All kinds of things are clickable. Try clicking the various links and icons you see. There’s masses of great information available here.
See which posts are popular, where visitors came from, what they clicked on, their search terms. Track posts over time. Track visitors by day, week and month.
There’s enough here to keep you happy for a long while.