Most often, it is difficult for someone to see if you are viewing their MySpace blog, especially if you are not signed in.  However, I know there are many tools and plugin programs for MySpace, and realistically, one would most likely allow you to track the IP number of your page views, which then shows your location as well.  If your identity is easily revealed by your IP number and location, then the individual may figure out who you are.  However, most likely than not, the majority of users would not be using this type of software or plug-in.