Dive summary:

• A study from Nielsen finds that PC users spend 20% of their time online using social media, and mobile users spend 30% of their time on social media sites.
• Mobile Web and mobile app use of social media is up 63% in 2012.
• Facebook had 152.2 million visits from PC and 78.4 million users via mobile in July 2012, and that is twice as many users as any other social media website.

From the article:

… “Consumer attitudes towards advertising on social media are still evolving,” noted Deirdre Bannon, Nielsen’s social media practice lead. “Though roughly one-third of social media users find ads on social networking sites more annoying than other types of Internet advertisements, research suggests there are opportunities for marketers to engage with consumers via social media.” …