Just wanted to point out that the FAQ for the main 40k rulebook has been recently updated.
Of note:
-- "Dedicated Transport" bought in the current IG and Black Templar codices can only be used by the unit that bought them. This applies to any codex that specifically states this as such.
-- Psychic powers CANNOT be used against units in transports (unless the psyker is in the transport with the unit). But this means that you can't Doom transported units, for example.
-- Models that can Turbo Boost may do so during a Scout Move. (old news, but it never hurts to reiterate)
-- Items and special abilities that allow a unit to re-roll leadership/morale tests cannot be used to help a unit that is falling back attempt to regroup. Apparently a Regroup test is a specific kind of test, so the item/rule would need to specifically say "Regroup Test" in order to affect these checks.
-- Should a single unit be large enough to be within 3 inches of multiple objectives, it can capture/contest them all.
-- The enemy player CANNOT use their opponents upgrades/items that don't specifically say that they only affect friendly models. For example, Necron's can't use another Necron's Res Orb or Monolith. Teleport/Homing Beacons only work for the army that bought them, and Nurgle-marked units' kills on the opposing side to Epidemus don't raise his special power tally.
-- An independant character CANNOT leave a unit that they arrive from reserve with (whether it be normal reserves, outflanking, deep strike, etc) until their next movement phase.
And now you know, and knowing really IS half the battle.