"This card is colorless."
I'm assuming since it says "card", this means no matter what zone it's in, it's colorless? And since it's Devoid, it gets around Protection?
From mtgsalvation:
Devoid was introduced in Duel Decks: Zendikar vs. Eldrazi, as a preview for Battle for Zendikar. [2] Because it is a characteristic-defining ability, cards with devoid are colorless at all times, including when not on the battlefield or outside of the game. However, devoid does not change a card's color identity, which is defined as the combination of all colors indicated on the card.
Since the permanent/spell with devoid has no colors, it can target things with protection from colors.
Another fun interaction comes with Intimidate.
Since it has no colors, it can only be blocked by artifact creatures. Two colorless creatures do not share a color...