“The Sex Factor,” a Web-based series promising a $1 million prize and “instant” superstardom. It will be hosted by Belle Knox, she of recent Duke University fame, and judged by porn stars Keiran Lee, Tori Black, Lexi Belle and Remy LaCroix. The contestants, eight women and eight men, will have no prior experience in the adult industry. They will be put through a series of adult challenges — from nude modeling to sex on camera — and the viewers will decide the winners via Twitter.