Emily Weiss had no cosmetics industry experience when she founded Glossier, a beauty brand for the Instagram generation. What she did have: reams of insider info on what women actually wear -- and want -- out of skincare and makeup thanks to her popular blog Into The Gloss. In Glossier's first year in business, she raised over $10 million in funding. "It wasn't easy," said Weiss. Here's how she's using the Internet to build better beauty products.