Facebook is apparently getting a lot more unfriendly.

Users are getting a lot more selective, deleting comments, photo tags and even friends at a record rate, according to a new study released Friday by the Pew Internet and American Life Project.

Pew is calling this phenomenon "the pruning" of social networks, and the study includes findings like this: 63 percent of users have unfriended people from their friends users. Another 44 percent have deleted comments made by others from their profile page, and 37 percent have removed tags from photos.

"Social network users are becoming more active in pruning and managing their accounts," says the report, written by Mary Madden, senior research specialist at Pew.

Users are also taking an active role in keeping their private information private, with 58 percent of users saying they use high-level privacy settings so only friends can view their pages. Women are far more restrictive, with 67 percent using the tightest privacy settings, compared to 48 percent of men. They lock down their accounts despite the fact that half of all users say they have "some difficulty" using the privacy controls.

The research seems to suggest that U.S. adults, who have so far shown little appetite for actively managing their personal privacy, are starting to get the hang of it.

"Social science researchers have long noted a major disconnect in attitudes and practices around information privacy online. When asked, people say that privacy is important to them; when observed, people’s actions seem to suggest otherwise," the report noted. The shift to more privacy on Facebook seems to belie this long-standing trend.

Perhaps regret has something to do with that.  The report found that 11 percent of Facebook users say they've posted something that they regret on a social network. Men are twice as likely to say so (15 percent to 8 percent). Users 50 and older, at 5 percent, are much less likely than young adults under 29 (15 percent), to express such regret. 

One area where there was a surprising lack of age gap: Overall privacy settings. While 23 percent of users 65 and over choose fully public settings, 22 percent of users 18-29make the same choice.

"The choices that adults make regarding their privacy settings are also virtually identical to those of teenage social media users," the report said.  "Private settings are the norm, regardless of age."

Young adults are more likely to "unfriend," however at 71 percent, compared to just 41 percent for the oldest users.

The Pew report is based on a survey of 2,277 U.S. adults conducted in May, and has a margin of error of +/- 3 percent.  In nearly all "pruning" related categories, and within nearly all age groups, use of privacy-related tools gained ground since the last time Pew conducted the study in 2009. Back then, only 30 percent of all users had untagged a photo, compared to 37 percent in 2011; and 56 percent had unfriended someone, compared to 63 percent in 2011. 

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