Primedia has acquired a majority stake in Automotive.com for $72.5 million in cash, reports MediaWeek. Primedia will initially maintain an 80 percent stake; the remaining 20 percent will be acquired no later than early 2010. Automotive.com's network of sites reaches 12 million users per month; other auto-related Primedia properties include MotorTrend.com and HotRod.com.