This deck's main features are:

• A core of aggressive mill cards. Glimpse the Unthinkable, Breaking, and Archive Trap are fast. The Jaces, Haunting Echoes, and Snapcasters flashing back your early mill cards, round out the top end.
• Card draw. It takes about five of your mill cards to kill an opponent. Unlike a burn deck, your cards aren't fast or flexible enough to just run a deck full of kill conditions. Thus, without card draw, it's easy to get into nasty situations where you're treading water hoping to topdeck the right card. Visions of Beyond is an Ancestral Recall in this deck. This decks' designer is taking a risk with Howling Mine, which draws cards for both you and your opponent, but he's counting on mill being an unexpected deck, so most of the extra cards his enemies draw won't interact well with his. Shelldock Isle sneaks a bit of extra card advantage into the deck.
• Discard, not counters. Most dedicated combo decks will be faster than you, so you want to do something to slow them down. Likewise, a lot of other decks may sideboard "silver bullet" answers that you really want to take out. However, using counterspells requires holding mana open, sometimes for turns on end — which you can't do, since most of your kill cards are sorceries, and you want to cast a bunch of them quickly to power up Visions of Beyond and Haunting Echoes in the later game. Discard spells like Thoughtseize offer very mana-efficient disruption that you can use on your own timetable rather than your opponent's (though you do need to keep your opponent's deck in mind for optimal timing).
• Anti-creature speedbumps. Your pinpoint disruption will slow down combo decks, but it does very little against aggressive creature decks that don't really care about losing a single card (especially if it costs them two life). Damnation and Ensaring Bridge (you're emptying your hand very aggressively) take care of a lot of threats at once. Ensnaring Bridge is also good against the kinds of midrange decks that can use one big creature at a time to get past your Damnation.
• Land destruction. Big formats are full of powerful lands. In Modern, a particular concern is Tron. Once the Urzatron is assembled, the deck is very hard to stop (especially if they've fetched the Eye of Ugin as well). Ghost Quarter in the main deck and Fulminator Mage out of the sideboard help you aggressively attack their lands. Ghost Quarter also covers a gap in your Damnation strategy: it kills removal-dodging manlands like Inkmoth Nexus and Treetop Village.
• No Hedron Crabs! Modern is full of creature-based decks. So pretty much everyone is running creature removal. Without many other targets in your deck, they will just throw their removal at your your Crabs. The card's also a terrible late-game topdeck since it hardly does anything on its own.
• Surgical Extraction is your best friend. This card is a really important part of the deck. Without it, you are actually accelerating any graveyard deck you fight against. Combined with your aggressive mill plan, Surgical Extraction can neuter a lot of combo decks. It's also a lynchpin against Tron: extracting any of their Urza lands buys you three extra turns at least — and removing Emrakul in response to its shuffle trigger is the only way to mill them out at all.

The big lesson here is that Glimpse-based mill doesn't play like a typical combo deck. It's more like burn: a bunch of interchangeable kill cards and a few answers to slow down fast decks or get past silver-bullet showstoppers.

This deck is targeting a specific metagame, but there are some general conclusions we can draw:

• A core of aggressive mill cards. Glimpse the Unthinkable, Breaking, and Archive Trap are fast. The Jaces, Haunting Echoes, and Snapcasters flashing back your early mill cards round out the top end. Really the main takeaway here is that you want about a quarter of your cards to mill the opponent, and a couple of those should be repeatable mill (Jace).
• Card draw. It takes about five of your mill cards to kill an opponent. Unlike a burn deck, your cards aren't quite fast or flexible enough to just run a deck full of kill cards. Thus, without card draw, it's easy to get into nasty situations where you're treading water hoping to topdeck the right card. Visions of Beyond is an Ancestral Recall in this deck. This decks' designer is taking a risk with Howling Mine, which draws cards for both you and your opponent, but he's counting on mill being an unexpected deck, so most of the extra cards his enemies draw won't interact well with his. This decks sneaks a bit of extra card advantage in with Shelldock Isle.
• Discard, not counters. Most dedicated combo decks will be faster than you, so you want to do something to slow them down. Likewise, a lot of other decks may sideboard "silver bullet" answers that you really want to take out. However, using counterspells requires holding mana open, sometimes for turns on end — which you can't do, since most of your kill cards are sorceries, and you want to cast a bunch of them quickly to power up Visions of Beyond and Haunting Echoes in the later game. Discard spells like Thoughtseize (or its budget-friendlier cousins Duress and Inquisition of Kozilek) offer very mana-efficient disruption that you can use on your own timetable rather than your opponent's (though you do need to keep your opponent's deck in mind for optimal timing).
• Anti-creature speedbumps. Your pinpoint disruption will slow down combo decks, but it does very little against aggressive creature decks that don't really care about losing a single card (especially if it costs them two life). This particular version picked Damnation and Ensaring Bridge (you're emptying your hand very aggressively) take care of a lot of threats at once. Ensnaring Bridge is also good against the kinds of midrange decks that can use one big creature at a time to get past your Damnation.
• Land destruction. Big formats are full of powerful lands. In Modern, a particular concern is Tron. Once the Urzatron is assembled, the deck is very hard to stop (especially if they've fetched the Eye of Ugin as well). Ghost Quarter in the main deck and Fulminator Mage out of the sideboard help you aggressively attack their lands. Ghost Quarter also covers a gap in your Damnation strategy: it kills removal-dodging manlands like Inkmoth Nexus and Treetop Village.
• No Hedron Crabs. Modern is full of creature-based decks, as are many casual environments. So pretty much everyone is running creature removal. Without many other targets in your deck, they will just throw their removal at your your Crabs. The card's also a terrible late-game topdeck since it hardly does anything on its own.
• Against tournament decks, Surgical Extraction is your best friend. This card is a really important part of the deck. Without it, you are actually accelerating any graveyard deck you fight against. Combined with your aggressive mill plan, Surgical Extraction can neuter a lot of combo decks. It's also a lynchpin against Tron: extracting any of their Urza lands buys you three extra turns at least — and removing Emrakul in response to its shuffle trigger is the only way to mill them out at all.

The most important thing to remember is that Glimpse-based mill doesn't play like a typical combo deck, where you're trying to assemble a card from column A and a card from column B. It's more like burn: a bunch of interchangeable kill cards and a few answers to slow down fast decks or get past silver-bullet showstoppers.

U/B Mill by Dan Paille
SCG Invitational Qualifier 11/03/2013

U/B Mill (Modern)
Dan Paille — 8th place, SCG Invitational Qualifier, 11/03/2013