In less than two years, Whatnot has become the most valuable independent livestream shopping company in the U.S. The platform for collectible trading cards, comic books and toys just raised $150M in a Series C round from venture capital firms, valuing it at $1.5 billion. Whatnot co-founder Grant Lafontaine spoke with Modern Retail about the future of livestream e-commerce, what draws investors to the space, and how his company plans to preserve its identity even as it plots its live video takeover.