Why are these classes the META? What do they do?

• SCOURGES: Boons stripping/corrupting. Jobs: Remove boons from opponents while applying conditions and outputting damage.
• WEAVERS: AoE Damage/Crowd Control. Jobs: Drop AoE Damage on opponent zerg, use CCs in Warrior Bubbles Winds of Disenchantment .
• HERALDS - RENEGADES: AoE Spike Damage/Support. Jobs: Range - AoE Spike Damage using Hammer: Coalescence of Ruin, Phase Smash on bombs, CC inside Winds of Disenchantment using Drop the Hammer. Jobs: Support Stances: Legendary Dwarf Stance - "Roads" Inspiring Reinforcement applies Stability to Party, Rite of the Great Dwarf applies 50% damage reduction on hard pushes or emergencies. Legendary Demon Stance - Pain Absorption applies Resistance negating the effects of conditions. Legendary Dragon Stance - "Boon bot" stance, able to apply Regeneration, Fury, Swiftness, Might, Protection and Superspeed to party members, offensively can apply conditions and damage.
• SPELLBREAKERS: Damage/Boonstrip. Jobs: Drop Winds of Disenchantment on enemy zerg. Also called Warrior Bubble.
• FIREBRANDS : Healer/Condition Clearer/Boon Applier. Jobs: Provide Stability , clear parties conditions, heal party members, apply boons.
• CHRONOMANCERS : Zerg Support/Crowd Control. Jobs: Copies and applies aditional boons to party members, provides stealth for zergs using Veil , CC in warrior bubbles with pulls from Temporal Curtain and Gravity Well.

Classes: Firebrands , Spellbreakers, Heralds, Chronomancers. Position: Frontliners Melee/Frontliners provide the support for the zerg. Firebrands keep their party members safe, healing and providing boons, negating the damage between the Casters and the enemy group. Spellbreakers' Winds of Disenchantment or 'Bubbles' are placed on top of the enemy zerg removing boons every second they are in the bubble and preventing them from receiving any new boon. Bubbles also negate the effects of projectiles. As the bubble is placed, Heralds and Chronomancers will CC the players within the bubble, while the caster are dropping AoE damage catching the enemies without boons, making them easier targets to be killed. A correctly placed bubble coordinated with a good bomb engage from the casters can easly kill 10-20 players that are caught off guard.

Classes: Weavers, Scourges, Heralds. Position: Left or Right the Melee Train Backliners jobs: keep constant pressure on the enemy zerg with light AoE damage providing overall controll of the fight, saving Heavy AoE damage for bombs. Scourges will use their Staff low-cooldown marks to provide small pressure to keep the enemy zerg from full pushing, saving up F1 Manifest Sand Shade for the bomb due to the recent Sand Savant change. Weavers will provide with Staff Water 2 Ice Spike, Staff Fire 2 Lava Font and Heralds with Hammer 2 Coalescence of Ruin. All big cooldowns are held for Winds of Disenchantment . After a successful Bubble is placed, Scourges will bomb with Shades stripping more boons in the bubble, Weavers will CC with Staff 4 Water Frozen Ground, Staff Air 5 Static Field and Staff 4 Earth Unsteady Ground. Heralds will do the same with Hammer 5 Drop the Hammer. Holding them in the bubble allows the boons to be stripped more and be able to apply more damage, at this time you procede with your big AoE damage.

There are different ways to lead/be part of a fight. Here are two of them:
MELEE BALL: All squad members stack tightly and stay with in a 600 range or less of each other training down the enemy. Pros: Excellent sustain for all party members, stay close, easy to ressurrect if one of your members goes down. Cons: Allows enemies to easily bomb your group, allowing them to apply alot of pressure. PIRATESHIP: Very few frontliners in squad, mostly backliners and range classes that can cast from 900-1200 range. Pros: Provides alot of damage, can keep distance, makes it easier for casters to run higher damage builds. Cons: Easy to be pushed, not enough frontliners to protect backliners, wipes quickly with lack of support. CLOUD FORMATION: The cloud, if organized properly, is the most annoying and frustrating blob to fight. The way it's achieved is by spreading the casters on all sides around the enemy blob, making it hard for them to localize damage on a single spot, even if your melee of Firebrands is still tight because they can self sustain and bait the damage off everyone else. When fighting a cloud you will receive random bombs from all sides, but often not a hard enough engage to downstate 40 players all together. The cloud will start to generate downstates of the people most on the sides, especially those tailing behind because they are the most vulnerable. How do you counter a cloud formation? The sustain of your squad has to be quite good (unless the enemy damage is really weak), just like they are generating downstates from your sides, you have to do the same. To generate downstates you will need to start pulling people in groups with Firebrands F1 Tome of Justice skill #3 Heated Rebuke and Chronomancers focus skill Into the Void , those will group up a bounce of enemies that you are free to bomb as Scourge or Weaver. Usually this is not a very good approach to the fights but everything is based on the current situation of the squad composition, the general skill level, the servers you are fighting and where you are fighting. This option would be a last resort if the blob is really struggling with coordination.

What is the commander calling when speaking on TeamSpeak or Discord? Here are some words you might hear while a commander is leading a fight:
BLAST: Blast Finisher Skills on friendly AoE fields (Waters, Stealth, Fire fields etc). BOMB: Big AoE/Spike Damage on the commanders call. BUBBLE: Winds of Disenchantment also known as Warrior Bubble. CC: HARD CC - Knockback, Knockdown, Pull, Float, Daze, Launch, Sink, Stun, Fear, Taunt. SOFT CC - Blinded, Chilled, Crippled, Immobile, Slow, Weakness. CLEANSE: For Firebrands to cleanse the conditions fo their team mates. DOWN: For an enemy player who has gone into downstate making the enemy group smaller ensuring it doesn't get back up. Also a call to ressurrect one of your group in downstate. EMPOWER: Empower is the base staff #4 skill for Firebrands used to stack might before the fight, and a way to regroup with the tail of the group. LINE: CC skills like Line of Warding or Unstead Ground. MARKER: Where the commander places a squad marker and wants you to either watch, apply pressure or bomb when they call for it. METEOR/CHILL/STATIC/WATER: Vocal Weavers calling their skills whether its a heal for the zerg to blast, CC in bubbles or AoE damage for Bubbles. PUSH: When the Melee train is pushing and everyone needs to stay in range of each other for heals to get through enemy bomb or catch the enemy as they retreat. RESISTANCE: Resistance is boon for negating condition damage. STAB/STABILITY: Stability is a boon that prevents you from getting hard CC. Every Hard CC you hit removes one stack of Stability. VEIL: Veil is a mesmer utility skill used to apply stealth to the squad. This allows the squad to move without being seen and allows for a semi surprised attack on the enemy group. WELLS: For Scourges to cast Well of Corruption and eventual Well of Suffering.

Here are some links that can help: General WvW wiki How servers work Boons/conditions conversion table WvWstats matchups page Gw2Timer WvW interactive page