Privacy worries have bedeviled Facebook since its early days, from the introduction of the endless scroll of data known as the news feed to, most recently, the use of facial recognition technology to identify people in photographs.

At the nub of all those worries, of course, is how much people share on Facebook, with whom and — perhaps most important — how well they understand the potential consequences.

The company has struggled to find a balance between giving users too little control over privacy and giving them too much, for fear they won’t share much at all. Seeking a happy medium, Facebook announced changes on Tuesday that it says will help users get a grip on what they share.

When the changes are introduced on Thursday, every time Facebook users add a picture, comment or any other content to their profile pages, they can specify who can see it: all of their so-called Facebook friends, a specific group of friends, or everyone who has access to the Internet. These will be indicated by icons that replace the current, more complicated padlock menu.

Similar controls will apply to information like users’ phone numbers and hometowns and whether they like, say, death metal bands, on their profile pages. Users will no longer have to seek out a separate privacy page to tweak who sees how much of that personal information. Nor will they have to bother to remember what those settings were.

Company officials say they hope the changes will simplify the process of establishing who knows what about your life on the Internet — and hopefully, save a few people the embarrassment of unwittingly sharing too much.

“We want to make this stuff unmistakably clear,” Chris Cox, vice president for product at Facebook, said in an interview. “It has to be clear that Facebook is a leader in how people control who sees what.”

Implicit in these changes is the challenge brought on by Facebook’s own success. It is used by 750 million people worldwide, with varying degrees of knowledge about what it means to have a life online. There is the looming prospect that the company will go public, along with the abiding concern about potential government regulation or litigation stemming from privacy issues.

Not least, there is the need for Facebook to cultivate the trust of its users, amid growing competition from Google’s nascent social networking service, Google Plus, which emphasizes more compartmentalized communications with different sets of friends and acquaintances.

Facebook dismissed the notion that the changes were fueled by competition. Company officials took pains to tell reporters that they had briefed privacy advocates on the changes — including those who have been critical of Facebook — and solicited their feedback.

It is too early to tell whether users will find the changes more inviting or simpler, or whether they will reduce what Kurt Opsahl, a lawyer with the Electronic Frontier Foundation, called “the amount of unintentional oversharing on Facebook.”

Privacy advocates warned that the new tools did not address a concern about sharing location. One Facebook user can publish information about another user’s whereabouts without his or her consent — whether it’s an employee at the beach on the day he or she called in sick or a husband at a strip club without his wife’s knowledge.

Other privacy experts say that if users believe they have control over who sees what, they are more likely to share.

“I think it’s part of an evolution to push back at the notion that Facebook is trying to trick you into sharing,” said Jules Polonetsky of the Future of Privacy Forum, which is based in Washington. “You’re more likely to do so when you know what you’re doing.”

The new tools represent a departure from Facebook’s more recent approach, in which users found much of what they posted — tags, photos and so on — to be widely accessible unless they explicitly specified otherwise. The default position, in other words, was to opt for sharing.

Mr. Cox said the new tools were meant to demystify privacy controls and ensure that Facebook users were never “surprised” by what others could see about them.

That includes pictures in which they have been “tagged.” No longer will an unflattering or compromising photograph appear on your profile page without your consent, though the publisher of the photograph can still keep it up on his or her own page. Users will be able to approve every picture in which they are tagged before it appears on their profile pages.

Additionally, the privacy option that is now called “everyone” will instead be called “public.” Facebook executives say they want to dispel any doubts about what the setting means. If you click “public,” that means anyone who is online can see what you are posting, including perfect strangers — or, worse, parents, prospective employers and your ex-wife’s divorce lawyers.

“We need to offer fine granularity in order to be a universally usable tool,” Mr. Cox said. With the new settings, “it’s more visual and prominent who the audience is.”

Indeed, company officials say feedback from users suggest that pictures work better than words. So now, icons guide the way. “Public” is represented by a globe; “friends” by a pair of heads.