One out of six minutes on Facebook for average Americans. With women spending four times the time. Consumer brands, from the beer giant Budweiser to start-ups like the clothier Trunk Club, want to reach people where they are spending their time. More and more, that place is Facebook. In June, the social network accounted for about one of every six minutes that Americans spent online, and one of every five minutes on mobile phones, according to comScore, a research company.