What's not to like? Well, a lot actually. Facebook grabbed the world's attention yet again yesterday, as millions of users reported seeing a variety of NSFW images appearing in their News Feeds including porn, dead animals, and "extreme violence," courtesy of a widespread spam attack. The culprits are still unknown, but they likely took advantage of weak passwords or inserted malware in otherwise innocuous-seeming messages.

Social media ad spending is expanding at a healthy clip, and geotargeted social media ad spending -- employing information about location to reach consumers in contextually appropriate ways -- is growing even faster, according to a new forecast from BIA/Kelsey, which has total geotargeted social media spending jumping from $400 million in 2010 to $2.3 billion in 2015. That's a cumulative annual growth rate of 33.3%, compared to a CAGR of 25.7% for social media spending overall, which is supposed to advance from $2.1 billion to $8.3 billion over the same period. Geotargeted social media's share of total social media …

A growing number of studies suggest that social media use is correlated with some negative psychological impacts -- not universally, but with enough frequency to warrant caution. There is also the entirely understandable fear of surveillance and invasion of privacy; together, we get a rather unsettling psychological brew.

The Mexican drug war has expanded to include social media, with this week bringing the murder of another blogger in Nuevo Laredo, just across the border from Texas -- if you believe the note that was left next to the decapitated body. The note identified the victim as a moderator of Nuevo Laredo en Vivo, a local blog about goings-on in the city which has become a forum for reporting drug-related crimes and warning the public about dangerous areas, and stated, "this happened to me for not understanding that I shouldn't report things on the social networks."

Groupon just succeeded in raising a mint of money -- $700 million -- with a limited IPO of 35 million shares last week. That values the company at around $12.8 billion, down from the heady heights of the $25+ billion range not so many months ago. But analysts are warning that the company may still be overpriced, given that there are essentially no barriers to entry for new competitors in the group discount arena.

Here's an interesting bit of context for the discussion about online "friends": the number of close friends listed by the average American has dropped over the last 25 years, according to a new study by Matthew Brashears of Cornell University, who surveyed 2,000 U.S. adults as part of a national series of "Time-sharing Experiments for the Social Sciences." The results are being published in an academic journal called "Social Networks."

The proportion of students who have been sexually harassed via social media, text, or email is lower than the proportion harassed in person, according to a new survey of 1,965 students in grades 7-12 conducted by the American Association of University Women in May-June 2011 -- but it's still alarmingly high. Thirty percent of students said they have been sexually harassed via electronic channels, compared to 44% experiencing harassment in person.

The ability to freely access social media in the workplace rivals other, more traditional considerations like salary when young professionals are weighing up employment options, according to Cisco Systems' recent "Connected World Technology Report," based on a global survey of 1,441 college students and 1,412 employees, ages 18-29, in 14 countries worldwide including the U.S., Canada, U.K., France, Germany, India, China, Japan and Australia. Social media access was just one of several important technological criteria cited by young adults for the ideal workplace; their wish list also included mobile access and the ability to work remotely.

Although there's been a lot of discussion about the potential for criminal prosecutions arising from online impersonation, New Jersey is one of the first states to see an actual prosecution for identity theft on social media. The lucky winner is Dana Thornton, a somewhat unbalanced-seeming 41-year-old woman from Bellville, NJ, who is accused of creating a fake Facebook page to defame her ex-boyfriend.

Niche audiences inhabiting "long tail" sites present something of a dilemma for marketers: desirable because they're highly engaged, their relatively small numbers (on any one site) nevertheless make it difficult to achieve scale. Martini Media is hoping to change that with a series of new ad programs offering rich media ads with story-telling capabilities on a variety of niche sites, including those with a high proportion of affluent audience members.