I love this idea of Keep Cup. The reusable coffee/commuter mug isn't new - but I always wondered how the baristas knew where the Grande fill line was (outside of filling a cup first and then pouring into the mug, in which case - doesn't that defeat the purpose?). Keep Cup provides standard sizes (also translated here in Starbucks speak): Small/Tall, Medium/Grande, Large/Venti.
What's especially sweet about the Keep Cup is that you can customize your color options! Genius.
You can even purchase in bulk, based on your custom color combo. Next, I'd love to see them offer a gift voucher so someone else may enjoy designing their own Keep Cup - from you! XO