I don't know if there's allready a list of general things that are good to know. If so, please merge then. Figured it'd be helpfull to summ it all up. Feel free to add things that are usefull to know.

- Buy Heirloom before 4.0.1 hits. The conversion on Emblems of Triumph into Justice Points is 1:2.74. So, 40 Emblems of Triumph = 110 Justice Points. Basic chest and shoulders however are 435 Justice Points. Same probably goes for WG items.

- Armor pen is removed. People will want new gems. Take note.

- Glyphs.Soon glyphs are going to be one time use items which teach you a spell in your spell book. This new ‘spell’ will then be turned on or off based on which glyphs you’d like to have at any given time
These glyphs will turn into charred glyphs, which will be useless and sell for 50s each to a vendor:
Glyph of Arcane Explosion (MAGE)
Glyph of Barbaric Insults (WARRIOR)
Glyph of Dark Command (DK)
Glyph of Disease (DK)
Glyph of Fire Blast (MAGE)
Glyph of Fire Ward (MAGE)
Glyph of Icebound Fortitude (DK)
Glyph of Last Stand (WARRIOR)
Glyph of Mana Gem (MAGE)
Glyph of Possessed Strength (HUNTER)
Glyph of Rapid Rejuvenation (DRUID)
Glyph of Scorch (MAGE)
Glyph of Siphon Life (WARLOCK)
Glyph of Survival Instincts (DRUID)
Glyph of Taunt (WARRIOR)
Glyph of Unholy Blight (DK
Glyph of Volley (HUNTER)

- Ammo has been removed from the game.