With 400 million active members, Facebook has a larger population than every country on earth except China and India. And it sometimes feels like most of us who use the service have one thing in common: We love to gripe about Facebook.  Lately, most high-profile complaints involve recent changes to the company's privacy policies. (I explained how to tweak its famously convoluted privacy settings in this story; founder Mark Zuckerberg says that simpler controls are on their way.) But there are plenty of other things about Facebook that prompt people--even Facebook fans--to grumble. The service is rife with little irritations, including ones that have the potential to be dangerous, such as as fraudulent messages from people who'd love to steal your passwords.  Herewith, five of those annoyances, and advice on how to respond to them--or prevent them from bothering you in the first place.  Annoyance: Excessive e-mail When your friends take actions on Facebook that involve you--such as tagging you in a post or photo, commenting on your Wall, adding a friend you suggested, or simply poking you--Facebook may send you an e-mail alerting you to the happy news. That can be useful, but the more active that you and your friends are on Facebook, the higher the chances that these notifications will feel like a tsunami of information overload.  How to fix it: Click on "Account" in the upper right-hand corner, then on "Account Settings." Then click on the "Notifications" tab. You'll see dozens of categories of Facebook events that can trigger an alert via e-mail or text message. You can turn any or all of them off. (You may well want to leave some of them selected, such as the one which e-mails you whenever a friend invites you to an event.)  Annoyance: Noisy News Feed Your News Feed is the first screen you see when you sign into Facebook--a never-ending update on your friends' recent activity on the service, such as when they've uploaded new photos or commented on another friend's post. But Facebook also lets applications which your friends have installed automatically add items to your feed. And if you haven't been sucked into the world of FarmVille, getting an impersonal update each time one of your buddies buys a tractor can can get old really fast.  How to fix it: Scan your News Feed for an item posted by an app you'd like to ignore. Hover the mouse pointer over it, and a Hide link will appear at the right. Click it, and you'll see buttons that will let you either hide all items from your friend, or items from the app. Unless your friend is just plain boring, it's that second link you want to click. Doing so will block the app from posting items on behalf of any of your friends.  Annoyance: Junk from strangers One of the nice things about Facebook's e-mail-like Messages feature is that you're much less likely to get inundated with spam than you are in plain old e-mail. But depending on your Facebook settings, it may still be possible for people you don't know to send you messages--including spammers, scammers, and others who you don't want to hear from. Most of these messages are pretty easy to spot, but it would be nicer if they never arrived in the first place.  How to fix it: If you receive a piece of spam in your Facebook inbox, click the Report Spam link. That will report it to Facebook so it can take appropriate action against the member who sent it. You can also configure your account so that only people who you've already friended can send you messages, which will make it dramatically tougher for spammers to pester you. Click on "Account" in the upper right-hand corner, then on "Privacy Settings." Then click on "Contact Information." Near the bottom of the list of options, you'll see "Send me a message." Change the setting to "Friends only" to prevent people you don't know from contacting you. (They'll still be able to attempt to add you as a friend, but you can accept or ignore these requests as they arrive.)  Annoyance: Junk from friends Even if you don't let random strangers invade your Facebook inbox, you may get a message from friends alerting you to something such as a video that he or she thinks you should watch right away. But the message may really from a hacker who has compromised your pal's Facebook account. And if you click on any links in it, you'll get routed off Facebook and onto a dangerous Web site which will try to do things such as steal your passwords or install malicious software on your computer.  How to fix it: Find friends who are less likely to let their Facebook accounts get hijacked. Or keep your pals, but be extremely skeptical of Facebook messages that ask you to click on anything. If in doubt, just don't click--and run a modern Web browser and an up-to-date security sute, both of which will include features designed to prevent you from unwittingly visiting dangerous Web sites.  Facebook knows a lot about you: your location, your gender, your age, your occupation, and maybe even your tastes in everything from food to music. It uses some of this data to display ads that target people like you. Which isn't an inherently bad thing--the targeting is anonymous, and increases the chances that you'll see ads you find interesting rather than irritating.  But cheesy advertisers sometimes buy ads with claims that are misleading at best--such as free iPad offers which claim to be available to everyone who shares your age and gender. (The "free" offer involves signing up for nightmarish quantities of marketing promotions, some of which cost money, and you see the ads whether you're a 23-year-old male or a 76-year-old female.) Facebook's policies prohibit tactics such as these, but the ads often pop up like weeds before the company knows they're there.  How to fix it: You can't guarantee that you'll never be exposed to a questionable ad--but when you do see one, you can take action. Click on the "x" to the right of the ad to close it. Facebook will ask you why you want to get rid of it. One of the options is "Misleading." If you click on that, and Facebook agrees with your appraisal, that particular ad will never bother a Facebook user again. Harry McCracken blogs at Technologizer, his site about personal technology. He's also the former editor in chief of PC World. Follow him on Twitter as @harrymccracken.
Here's fast relief for some of the social network's most maddening issues, from never-ending e-mail alerts to spammy messages from random strangers.