That is strange. In your example, this site brings me to post 100. UNLESS I have visited the site on my own since I received the email (ie I received the notification email, didn't open the link in the email right away, but before I did open the link, I happened to open garagejournal to check reviews on a tool, closed garage journal, clicked the link in the email later in the day, and now it would not bring me to the post it describes in the email, it will be bring me to the latest post (if there was one) since I left after checking reviews on the tool.
The link in the notificaiton email is not linking to the specific post it quotes in the email or anything like that... it is a special link that brings you to the newest post in the thread since you last visited any part of the garage journal forum, whether you viewed the subscribed thread/post or not. It is not a link to the newest post since the last time you visited the thread you are being notified for. Each notification email actually contains the exact same link... you could click the link from any notification email (for the same thread) and it would bring you to the same place, which again is the newest post in the thread since you last visited any part of the garage journal forum. I hope this is not too confusing of an explanation.
In an ideal world, it would keep track of whether or not you actually visited the particular thread, but it doesn't, so if you ever visit the GJ forum and do not view the threads you are subscribed to, you kind of break the notification functionality wind up missing a bunch of posts if you don't scroll up.