Hmm. This is weird because it's happening with two different apps (FF and Safari) it must be something to do with my connection. I was at the Plex forums just a couple of hours ago and when I pull that link up from my History it still takes me to WP.com.
Edit: I switched accounts and fired up Safari. Same problem - I was taken to wp.com. I used my wife's macbook and was able to get to plexapp.com fine. What possibly controls where you go in your web browsers that is system wide on a computer? This is peculiar.