Peak Legend Rank (Season 3): 777
Mission Statement: Rely on spells and taunts, including the Ancestral Healing + Injured Blademaster combo, to make it to the late game, then lock the board down with a nearly endless supply of Earth Elementals (using Ancestral Spirit and Faceless Manipulator). The deck can win other ways, but if the game goes long enough this usually works.
(Thank you FromDust for the pic; my record is 4 Earth Elementals at the same time.)
The Story: I was playing my Divine Control Paladin when I faced a player named Loboguerrero. I was surprised when he played Earth Elemental, a risky card in an environment rife with Big Game Hunters and The Black Knights, but with Ancestral Spirit and Faceless Manipulator, the Earth Elementals gained value and seemed nearly endless. I gritted my way through the first four Earth Elementals, but the fifth one did me in. I instantly fell in love with the concept and made my own Ancestral Shaman. I fine tuned it throughout the course of the season, taking it from Rank 13 to Legendary.
The Meta: I think this is a good meta call right now. The copious taunts hold up well against Aggro, Zoo, and give you a shot against Miracle Rogue, while the strong removal options and threatening minions let you outlast most control decks. Opponents will generally expect that you are playing the standard Shaman build. That build has few threats, so opponents will often waste removal on some of your only mildly threatening cards like Fire Elemental, Azure Drake, and even Mana Tide Totem. They will also become detrimentally defensive when they drop into the standard Shaman's burst range of about 18 health. This deck runs almost no burst favoring the Earth Elemental lockdown, but it still benefits from this expectation.
Earth Elemental: This card is usually risky because of its vulnerability to Big Game Hunter and The Black Knight. It costs you 8 mana total and can easily wreck two turns. You should only play this on turn 5 out of utter desperation. The objective is to combo it with Ancestral Spirit and/or Faceless Manipulator to cement its value, burn out the opponent's removal, and hopefully lock down the game.
Ancestral Spirit: Ideally comboed with Earth Elemental for an extremely resilient wall, but can be reasonably comboed with Kel'Thuzad, Fire Elemental, or Injured Blademaster (you get a 4/7 back). Sometimes you just need taunt, so playing it on Sen'jin Shieldmasta is even an option. Finally it can proc (and give future procs) to Wild Pyromancer.
Ancestral Healing: Ideally comboed with Injured Blademaster for an early sturdy taunt. Often draws some hard removal making your Earth Elementals stronger later. Ancestral Healing can also be comboed with The Black Knight for the equivalent of a Chillwind Yeti and an Assassinate at a 3 mana discount. Also useful for emergency taunts or healing up an Earth Elemental (especially just before it is copied with Faceless Manipulator).
Some Other Cards:
Feral Spirit: I only run one of these because in my mind it is a situational card. In the early and mid game when the opponent has only 5 or less attack minions, it essentially functions as a 2/6 taunt that is vulnerable to AoE (and less vulnerable to single target removal). This is not worth 5 mana even if it is spread out over two turns and even against aggro. Later though it is very effective at slowing big threats and blocking finishing combos. You should almost always mulligan this card away and hope to find it later if and when you need it.
Unbound Elemental: A good turn 3 play if you haven't found your Injured Blademaster + Ancestral Healing combo yet. The 4 health helps it stick to the table and with 7 overload cards it can actually get somewhat threatening (maybe draws a silence). It may be worth replacing these with Earthen Ring Farseers to help against Miracle Rogue and Alexstrasza (especially in Freeze Mage).
Sen'jin Shieldmasta: Could have easily been Chillwind Yetis instead, but the extra taunt goes a long way against aggro toward surviving to play an Earth Elemental combo. The extra taunt also helps to block finishing combos.
The Black Knight: A good card in this meta all by itself, since everything but Aggro and Miracle Rogue are forced to play taunts to survive them. Also, the most popular aggro, Zoo, runs taunts of its own. The Ancestral Healing combo (cast Ancestral Healing on an enemy minion to give it taunt, then use The Black Knight's battlecry to destroy it) ensures its inclusion.
Ragnaros the Firelord (replaced): I felt that this deck needed one more big threat past the elementals. I experimented with Alexstrasza for the heal after stabilizing, but Ragnaros feels a bit more versatile. Often a good target for Ancestral Healing to make sure your opponent can't just ignore Ragnaros for the win. Its vulnerability to Big Game Hunter sometimes just ends up helping your Earth Elementals.
A list of the most common matchups I faced on my way to legend. Some mulligan information is included and I rate them according to how well this deck performs against them.
Handlock (Strong): You must be patient. Shamans usually hold Handlock healths hovering in the high teens range and then finish them with a windfury Rockbiter Weapon burst of some sort, but this deck does not have that ability. Instead you have to outlast the Handlock, which sometimes even means literally waiting for the opposing Handlock to run out of cards before making your move. The key is that Handlock actually has fewer threats than you might think: 2 Twilight Drakes, 2 Molten Giants, 2 Mountain Giants, and 1 or 2 Faceless Manipulators. They may also have Alexstrasza (this makes the matchup more difficult). Earth Shock can kill one Twilight Drake while The Black Knight and Hexes can kill three giants. The rest you can kill the hard way. I usually won't attack the opponent's hero until I can handle all of the remaining threats hitting the board on the same turn. This means trading on the board as much as possible and just not attacking a lot of the time. Beware of the Leeroy Jenkins + Power Overwhelming + Faceless Manipulator, 20 damage finisher. Avoid taking damage as much as possible, and have the appropriate number of taunts down to block it. The main danger is falling too far behind in card advantage, so don't overextend on the board for fear of Shadowflame or Hellfire. Finally, try to draw out his Faceless Manipulator(s) before dropping an Earth Elemental + Ancestral Spirit combo.
Zoo (Strong): Mulligan for early drops (4 or less mana), Lightning Bolt, Ancestral Healing, Wild Pyromancer (now removed), Lightning Storm. If you get a Wild Pyromancer or a Lightning Storm by turn 5 you're probably fine. Taunts help you stall until you get it together. Save Lightning Bolt for Knife Juggler or Dire Wolf Alpha if you can. Likewise, save Hex for Doomguard. No need to wait much on Earth Elementals in this matchup since there's no hard removal. If you get one down with Ancestral Spirit, that pretty much ends it.
Control Warrior (Strong): Another patient matchup. Try to save Hexes for truely scary minions, like Sylvanas Windrunner, Cairne Bloodhoof, or Alexstrasza. As a general rule, trade on the board rather than using removal if you can, since Warrior will probably be able to efficiently remove them next turn, and you're not going to rush him down.
Miracle Rogue (Fair): Mulligan for Lightning Storm, Bloodmage Thalnos, Wild Pyromancer, early drops, and Lightning Bolt when facing Rogue. You might even keep a Mana Tide Totem for a turn 3 play, since miracle rogue has to spend removal on it just the same (and you get a card back). Your first goal is to find Lightning Storm + spell power and/or Wild Pyromancer by turn 5 so that you have a chance at killing a Concealed Auctioneer. While you wait play your early drops, but favor playing non-taunts over taunts, so that you can save the taunts to block the Leeroy Jenkins combo. Make sure to keep the opponent's board clear, because it is very difficult to make your own minions stick. Do this with Lightning Bolts and trading. It is key to burn the opponent's Saps, so play your cheap taunts like Sen'jin Shieldmasta and Ancestral Healing before droping your Earth Elementals. Try not to play Feral Spirit until after your opponent plays Blade Flurry; it can really shine in this matchup. Ultimately the shear number of taunts can prevent the Leeroy Jenkins combo and let you coast to victory.
Ramp Druid (Fair): Keep a Hex when mulliganing against Druid just in case they Innervate out a Chillwind Yeti. Druid has limited removal options, which should work to your advantage, but does almost guarantee they run The Black Knight and Big Game Hunter. Beware the Savage Roar + Force of Nature combo (minimum 14 damage). Make sure you have enough taunt if your health gets low.
Freeze Mage (Poor): Go, Go, Go! Kill them as fast as possible...but it probably won't work. Mulligan for anything that will do damage fast; forget cards that help with board control. Earth Shock is really helpful for unfreezing your minion or neutralizing a Doomsayer. If you really want to increase your odds in this matchup, try adding Earthen Ring Farseers in place of Unbound Elementals. Save them for after the opponent plays Alexstrasza. They're helpful in some other matchups too, especially Miracle Rogue.
If you have any more questions about matchups, card choices, etc. or suggestions, let me know in the comments!
Naxx Update: I have replaced Ragnaros the Firelord with Kel'Thuzad. Kel is great behind the many taunts in this deck or with Ancestral Spirit. He's almost like another win condition for the deck. Also Wild Pyromancer has been replaced with Loatheb. Loatheb belongs in almost every deck. In the mean time, AoE is a lot weaker these days because of all the new deathrattles.
News: It sounds like on Wednesday, July 2nd, Day9 will be playing this deck on his daily: http://day9.tv/d/Day9/day9-hearthstone-decktacular-23-crusher-shaman/ . Tune in; it should be fun!
The Hearthstone streamer, Realz, has been playing this deck on ladder with great success. He explains his reasoning very well, and it would be a great way to learn about the deck.
http://www.twitch.tv/realz_/b/543631041 (Starts playing the deck at 6 hour mark)
http://www.twitch.tv/realz_/b/543924429 (Continues playing and later modifies deck at starting at 1:05)
http://www.twitch.tv/realz_/ (His stream)
Some fans of the deck have provided video spotlights that explain card choices, matchups, and/or give example gameplay. Check them out for advice on how to play the deck. Enjoy!
Matt Sparks: https://www.youtube.com/watch?v=a3Xf2dkLxUM
Tim Clark features Crusher Shaman in an article from PC Gamer's Hearthstone Help series called "Three Fun Decks to Try": http://www.pcgamer.com/2014/07/09/hearthstone-help-three-fun-decks-to-test/