BusinessWeek looks at a Pew study on privacy and social media trends and finds many Millennials, long thought to be laissez-faire toward their privacy, are actively guarding their personal information:

Seventy-one percent of social networking users aged 18 to 29 said they'd adjusted privacy settings on social networks in order to make some information private, according to the survey. Among members of generation X, aged 30 to 49, 62 percent said they'd made such changes. And 55 percent of baby boomers aged 50 to 64 said they'd changed from the default privacy settings on a social network. "Contrary to common assumptions, young people are in many ways the most active managers of online identities," says Mary Madden, senior research specialist with Pew and co-author of the study.

Two things to say about this. First, as Facebook entered the mainstream and became a professional Yellow Pages rather than a streaming college yearbook, kids took notice and blocked more of their information from acquaintances they didn't know well -- or did know well, but professionally, and in a way that is unreceptive to 21st birthday pics.

Second, this isn't necessarily about Millennial privacy. It's about Millennial technological savvy. At the risk of ageism and gross generalization, twentysomethings tend to understand the minutiae of technology better than fifty- and sixtysomethings because they grew up with it. As a result, they know how to block photos from their work acquaintances and keep their list of friends off the Google results page.

It should be said, however, that if Millennials understood how privacy control worked even better than they do, they might not have made such a huff about Facebook's recent changes. In a way, we're all catching up to the technology.