The previously announced changes include new sections explaining how it uses people's information. The updates also reflect recently added features such as a new profile format called Timeline.
The new policy also opens up the possibility for Facebook to start showing people ads on outside websites, targeting the pitches to interests and hobbies that users express on Facebook.
The voting period started Friday and runs through June 8. The company had announced the changes in May, a week before its initial public offering of stock. Facebook's highly anticipated IPO landed with a thud, closing just 23 cents above its $38 offering price on its first trading day. The stock has declined another 26 percent in the two weeks since then.
This is the second time Facebook Inc. is letting users vote on policy changes. The first time was in 2009 when Facebook was a much smaller, privately held company with fewer than 200 million users.
It may be the last time, though.
Thirty percent of Facebook's 900 million users, or 270 million people, have to vote on the changes - for or against - to have the process be binding. Otherwise, Facebook considers the vote "advisory."
That will most likely be the case. Facebook's experiment in democracy hasn't panned out as expected. While thousands of people have left comments on Facebook's proposed changes, "our original intent was to get high-quality," and not high-quantity comments, said Erin Egan, Facebook's chief privacy officer of policy.
Facebook said it is still interested in getting user feedback on its policies, but it is reviewing how best to do so.
"While our participatory mechanisms may change, our commitment to greater transparency, accountability and responsiveness will not," Facebook vice president Elliot Schrage wrote in a blog post. "We will explore ways to bring user suggestions and concerns before Facebook's management."