I just checked out Amazon.com and the page for Leviathan by Mastodon.
According to that page people who bought Mastodon also bought Lamb of God Albums, Isis albums, Trivium albums, Killswitch Engage, Machine Head, The Mars Volta, High On Fire, Wolfmother, Meshuggah, Pantera, Porcupine Tree and a whole lot of Tool albums and needless to say, basically the entire Mastodon back catalogue (admittedly there were reasonable things as well like Dragonforce, which you should know I also don't approve of, Iron Maiden, again disapproval from me, early Metallica and Nine Inch Nails).
So yeah, people who like Mastodon seemingly tend to like the above bands as well. Now they are also obviously capable of good taste but I think we can begin to move away from the idea that bands don't tour with bands that are completely different in both sound and target audience.
Oh, and everyone jumping down my throat with attempts at withering remarks the moment I break in on your circle jerk about a band that, even if I do concede that they are "ok" in the grand scheme of things (afterall, they're no Drowning Pool which I had the misfortune to hear earlier), are not as great as you guys are making them out to be doesn't smack of hipsterism. Not at all, right?