Derek Rey, cofounder and VP of media and sales at social media endorsement vendor Ad.ly, discusses how his startup matches advertisers with celebrities like Charlie Sheen, Kim Kardashian, Mariah Carey and Paris Hilton. Ad.ly helps brands connect with consumers via the most influential celebrities, artists and athletes on the most popular platforms. More than 1,000 of the top celebrities in social media work with ad.ly to endorse brands, products and services to their fans. Toyota, Best Buy, Microsoft, American Airlines, NBC and Sony are among the 150 major brand advertisers that have worked with ad.ly on more than 24,000 campaigns. Ad.ly is pioneering the celebrity endorsement market in digital media, tapping the $50 billion spend on endorsements worldwide as well as the $35 billion spent in digital advertising. Based in Beverly Hills, ad.ly has raised more than $6 million in venture capital from GRP Partners, Greycroft Partners and prominent angel investors.