Facebook's newest features may make it easier to share with family and friends across the Web, but it seems not everyone wants to be an online social butterfly.
Last week, the popular social networking site unveiled a round of changes meant to make the Web more social and personalized, by expanding Facebook's presence to other sites.
On thousands of sites, including ABCNews.com, a "social plug-in" now lets users "like" content and see what their Facebook friends have liked, directly from those sites.
On three sites piloting an "instant personalization" feature, a user's profile information and friend list are automatically read by the site and used to shape the user's experience. On music site Pandora, for example, you can see what your Facebook friends like to listen to. On Yelp, you can see which restaurants they've reviewed.
But in recent days, some of those data-sharing changes have drawn criticism from Facebook users, privacy advocates and, most recently, federal regulators, who say Facebook needs to give its more than 400 million members more control over the personal information they disclose on the site.
"With great power comes great responsibility and sites like Facebook have great responsibility," Sen. Charles Schumer, D-N.Y., said Tuesday at a news conference on the issue. "In my view, it ought to be the user who determines who gets what information, not Facebook."
Joined by three other Democratic senators, Schumer sent a letter to Facebook, urging it to revisit its new policy and make it easier for users to control and protect their privacy.
One of their top concerns was Facebook's "opt-in" policy, which means that personal information is automatically shared with some partner Web sites unless the user goes through the process of disabling this feature.
"Grocery stores don't tell everyone what groceries you're buying and Facebook shouldn't tell everyone what your interests are, unless you want them to," Schumer said.
In addition to sending a letter to Facebook, Schumer asked the Federal Trade Commission to create guidelines for Facebook and other social networks to follow.
Calling the Internet the "Wild West," he said it was "utterly confounding" that almost no rules govern a Web site as massive as Facebook.
In a letter responding to the senator, Facebook said it takes privacy very seriously and that its new products give users "unprecedented control over what information they share, when they share it and with whom."
Facebook spokesman Andrew Noyes said, in an e-mail to ABC News, "We appreciate the concern raised by Sen. Schumer and expect that further dialogue with interested members of Congress about the user controls that accompany the tools announced by Facebook last week will alleviate any concerns they may have."
But privacy advocates point out that this is not the first time Facebook changes have triggered privacy concerns. In 2007, when Facebook unveiled Beacon, which tracked user behavior on other sites and shared the information on Facebook, user dissatisfaction was so strong that Facebook ultimately backpedaled and CEO Mark Zuckerberg apologized.
In 2009, the social network announced another set of privacy changes, which again sparked complaints from privacy advocates and Facebook users.