The Cozy Dog is on the south side of Springfield, at 2935 S. Sixth St., on what was once known as Route 66. They do have a web site, can’t remember what it is, though.
Someone else will have to chime in on the significance of the designations and stars on the Roadfood forums. I’m pretty sure that they reflect the number of times that you have posted to the forums, but exactly where the different cut-offs are, I’m not sure. I’m pretty new myself.