Online services like Facebook keep people closer together, but sometimes you need a bit of privacy. If you're tired of people always knowing when you're online, or if you just need a break from all the social interaction, there are several steps you can take to go incognito while using Facebook.
Facebook chat is perhaps the easiest way for your contacts to see if you're online. By clicking the "Options" menu within the "Chat" tab located in the lower right corner of your Facebook homepage, you can click the "Go Offline" tab to sign out of Facebook chat. This won't affect your ability to continue using Facebook normally. You can also create "Friend Lists" within chat, which enables you to create different sets of Facebook contacts. For example, if you want to appear online to family members but not casual friends, you can click the "Go Online" switch beside your "Family" list. This will keep you hidden from everybody except your specified contacts.
Even if you're signed out of chat, your Facebook contacts might be able to deduce that you're online by seeing your wall posts appear within their news feeds. Your privacy settings -- found within the "Account" tab -- allow you to customize what information gets posted to others' feeds. If you don't want any of your updates to be made public, you can set your preferences to "Private." As with chat, you can also create custom lists of friends so that some groups can see more than others.
If you need to communicate with your Facebook friends but don't want anybody else to know about it, messages give you a private way to interact. Just like emails, Facebook messages can be seen only by those to whom you send them. No notifications will appear on the walls of you or your recipient.
Social networking keeps family and friends connected, but it can also invite some unwanted attention as well. If you're trying to fly under the radar on Facebook because someone is harassing you or making you feel uncomfortable, you can take steps to keep him out of your business. On every Facebook profile is a "Report/Block This Person" link. Blocking a Facebook user means that he can't see your profile or any of your activity on Facebook. When you block someone, you also have the option to report any harassment or bullying.