As cliched as it sounds, the best way to learn about Facebook is to try it yourself. The fact that you're required to create an account, even if all you want to do is check the place out for yourself, says volumes about the myriad ways the social network tries to rope users in and keep everyone visiting and interacting. The fact that it's likely your friends, family, coworkers and business peers are already part of it can make it even irresistible to join. Setting up a page for your business is free, too, with optional advertising programs that cost money.
Origins
The original concept for Facebook remains somewhat of a mystery, depending on who is telling the tale and suing whom. But Facebook as we know it today began in 2004 when Harvard University student Mark Zuckerberg launched what he called "thefacebook," which was an online tool for fellow Harvard students to connect and share photos of themselves around campus at school events. The idea soon spread to other colleges, and eventually the public, and by late 2011 there were more than 500 million users, which, according to USA Today, represented 7 percent of the world's population.
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Many describe Facebook as a "social network" -- although Facebook uses the term "social utility," saying it's more useful and functional than just a connection tool. Whichever definition you prefer, the site offers users a variety of ways to publicly or privately share data about their life, and to find friends, classmates and others who might interest them. You can post public thoughts on others' pages, send them private emails or chats, search for people from your past or connect with people with the same interests as you.
Business Options
The preferred way businesses to connect with existing or potential customers is to create a business page which users can "like" to show their appreciation for, post questions or learn more about the business. Business page administrators, called admins, are given tools to see how much visits they receive and where they come from, and the ability to include Facebook details on their company sites or blogs so users can connect that way too.
Advertising
Though individual profiles and business pages are free, businesses can spend money on targeted advertising, primarily by creating ads that can be seen on the right-hand side. Users see different ads based on their histories -- who their friends are and what groups and sites they like. If an ad catches your eye, you're supposed to click on it. People also can pay to have certain posts be ranked higher on their friends' streams.
Apps
Facebook also relies on agreements with third-party companies which deliver content on its platforms. For instance, many of the games are created by other companies, who pay Facebook to offer their product on the site, and also receive data about the users who sign up for these games. Some games, such as Zynga's Mafia Wars, encourage users to invite other friends to play these games or post their activity on their friend or their friends' walls.
Privacy
Since its early days, Facebook has allowed users to control what others see about themselves. You can adjust your privacy settings under your account, and can go all the way from "everyone can see everything you do" to "only certain people can see anything." Users can block certain individual users, or allow users to see all their details only if a friend request has been accepted.