As the tooltip of Ribbon Dance - Spell - World of Warcraft says "Experience gained from killing monsters increased by 10%!" Which means only when you kill something that you gain extra xp. Well at the moment it actually also gives extra experience for gathering herbs and also arch/mining. Maybe even more. Just some pics of proof. Hope this helps you guys level. And this is not intended because of it's tooltip
Proof:
With ribbon:
Without Ribbon: