Brain-teaser Monday.

Advertising agencies built on crowd-sourcing platforms are popping up faster than a zit on Kate Perry. And recently I've had the pleasure of working with a couple of the best.

But despite their popularity there are still only a handful to choose from. Weed out the made-up agencies from the following list:

• Mob Rules
• Victors and Spoils
• CrowdSpring
• Adhack
• Hoi Polloi
• Guided Collective
• Rome
• Idea Bounty
• People are People
• Eeden Labs
• Tongai
• The Tea Party

Answer to last week's brain-teaser: c) Ghoul Britannia