So as of December, Twitter began offering clients another service: negative matching.
In real time, Twitter advertisers can adjust their campaign to avoid matching specific phrases or hashtag trends. That way, if a discussion about pizza turns into a discussion about anorexia or bulimia, for example, the advertisers can make sure their promoted messages do not appear in those searches.
YouTube also has mechanisms that give advertisers some control over where their brand appears. "When we become aware of ads that are showing against sensitive content, we immediately remove them," Lucas Watson, the company's vice-president for online video global sales, wrote in an email. "We also give advertisers control to target specific content, and they can choose to block ads against certain content categories or individual videos."
Last month, LinkedIn, the networking site for business professionals, clarified its terms of service to explicitly ban the selling of sexual services. "Even if it is legal where you are located," the terms read, users cannot "create profiles or provide content that promotes escort services or prostitution."
Hani Durzy, a company spokesman, said the decision had nothing to do with concerns about making the site safer for advertisers and was solely about making LinkedIn a better place for members. Still, the move comes as the site has been ratcheting up the promotional services it offers companies.
However, when Yahoo! recently acquired Tumblr, Marissa Mayer, Yahoo's chief executive, said the company did not intend to remove pornography from the social media blogging platform, even as it created more ad products for marketers.
Quigley, of the University of Texas, said he is sure more battles lie ahead and warned that trying to please big companies also had its pitfalls. "There is a danger of caring too much about what an advertiser cares about," he said. "Violence against women is one thing that is clearly over the line, but much of the rest of it is about politics, and that is much harder."
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