I think I figured out what a blog burst is.
If you have a blog where you post something new about Terri every day, you can be added to their list of Terri blogs. They supply a script for you to type into your blog, that will keep updated links to other Terri blogs on your blog. And of course, your blog will be listed there too. I think they currently have about 50 Terri blogs, and are shooting for 100.
The number of Terri blogs currently stands at 68.
http://www.prolifeblogs.com/articles/archives/2005/02/progress_is_bei.php