Pharrell Williams is a marketing genius. For his song "Happy" he has a music video that plays the song 24 hours a day. It is a 24-hour-long music video! Brilliant!

But he's not stopping there. He is writing a new "social book" called Inspiration. The book is actually available for anyone to read now but being the marketing whiz he is...words are missing.

He wants you to help guess the missing words. The first person to guess the missing word will have their name in his book. Check it out at http://tippex-socialbook.com/.