A couple of points to note here:
First, the router package you are using with the tutorial, Meteor Router, has been deprecated in favor of a now-canonical routing package for Meteor, Iron Router. You can see this noted on the Meteor Router github page here, and you can find the Iron Router specifications here. I suspect you may be using an older version of the Discover Meteor book as well, as it now covers Iron Router in detail. If at all possible, I'd try to get my hands on a version of the book covering Iron Router as it will be the standard for the foreseeable future.
Second, you are correct that that href="" property is not showing up because it is not rendering anything. Specifically, in Meteor 0.8+, if the value of an attribute returns null, undefined or false, the attribute itself is removed. Read more here.
Lastly, while I'm not up to speed on the details of Meteor Router it looks on quick inspection like you would want to pass PostPagePath the id and not the title of the post, e.g. {{PostPagePath id}} or similar.