Goo.gl URL shortening tool will show you where in the world people are when they use one of your links. The point that I was making was that it can be interesting to students to see how far something they share can spread. Goo.gl is not the only tool that will do this and it's probably not the best option if you want show students the global traffic of their blogs as a whole rather than showing the global traffic of just one post.
ClustrMaps is a free service that you can use to show students the global traffic sources of their blogs. ClustrMaps will display a real-time map of where in the world visitors are when they visit your blog. To get a ClustrMap for your blog just visit ClustrMaps.com, enter your blog's URL, and enter your email address. After your URL and email address are verified you will be able to get a ClustrMaps embed code to place anywhere on your blog.
Blogger users have a built-in set of visitor statistics that will show you where your visitors are coming from. To access these statistics select "Stats" from the drop-down menu next to the name of your blog when you sign-in at Blogger.com.
If you want to get really geeky with your blog statistics you can use Google Analytics to gather all kinds of information about visitors to your blog. To use Google Analytics you do have to add a bit of code to your site (Google Analytics offers good directions for doing this). Some of the statistics that Google Analytics will enable you discover are where visitors come from, which posts and pages are most visited, the top referrers to your blog, and how much time people spend on your blog.
Applications for Education
Depending upon which tracking method you use there is a lot that you and your students could do with blog visitor statistics. At the elementary school level looking at the geographic dispersal of visitors could lead into a geography lesson about countries and states. At the middle school and high school level you could have students investigate the visitor statistics to try to determine what keeps a visitor on a blog or why their blog posts are more popular in one location than another.