On the Internet, every day is April Fools' Day. On this day, newspaper headlines, R.S.S. feeds and tweet-streams are flooded with fake press releases, fake news items and prank headlines. Adding to the confusion, some companies will products on the day whose press releases will be mistaken for jokes. When Gmail was announced April 1, 2004, many people thought the then unheard-of offer of one gigabyte of free e-mail storage could not be true. But then, Google can only blame itself. The company is famous for April Fools' pranks like fictitious job openings for a research center on the moon, Google Gulp, a drink to make you smarter about making search inquiries and a broadband service called TiSP, or Toilet Internet Service Provider, that used wires strung through sewers. (Not a bad idea, really.) Thinking about how people get fooled on April 1 is a good way to prepare for the year-round attempts by swindlers to bamboozle the naïve, the witless and those who just aren't paying close attention. In other words, all of us.The same themes run through the e-mail solicitations of Nigerian princes waiting to share their riches, messages by banks to type in your PIN or frantic pleas from Facebook friends trapped overseas without any money. How do you tell the real from the surreal today? “Anything that's too good to be true requires skepticism,” said Baratunde Thurston, someone who knows a thing or two about how people react to information. He is an editor of The Onion. The Onion explicitly tries not to fool people — its fake news reports are satire, not hoaxes — yet readers have groaned that these days they cannot tell the difference between straight-faced CNN headlines and The Onion's parodies. A recent Onion video report that claimed that Stouffer's had added suicide prevention tips to the packaging of its single-serving microwaveable meals was retweeted by several suicide prevention groups. The Internet is a great place to fool people, Thurston said, because of what he called “tickerization” of news. Internet distribution means a lot more people can be fooled at once, and a much wider audience can watch the spectacle. One of the best way to prepare for today's pranks and scams is to study the classics. The quickest way is a walk through the April Fools' exhibit at The Museum of Hoaxes. You will begin to get the feel for the recognizable patterns to the most credible hoaxes, like the one in 1996, when Taco Bell put out a press release claiming that the company had bought the Liberty Bell and renamed it the Taco Liberty Bell. For the second phase of your education, head over to Snopes.com, the debunker of urban legends and klaxon of Internet scams. Click on “Top Scams” for information about advance fee scams or foreign lottery schemes. Bookmark the “What's New” section to track the latest hoaxes like Olive Garden, the restaurant chain, giving $500 gift certificates to people who sign up as Facebook fans or the threat of cockroach eggs in drinking straws. This is the first site to visit when you are the least bit suspicious about an e-mail message or Facebook posting. Facebook, which increasingly drives more traffic to Web sites, has been refreshingly candid about frauds being perpetrated on its pages. A list at facebook.com/security warns to watch out for fake toolbars, requests for passwords or messages that claim to be from friends in need of money in a foreign country. Adjust your privacy settings so strangers do not learn too much about you. Facebook posts a new warning almost every week. If you become a fan of the security page, you will be notified of new threats and tips posted there. Phishing is a malicious spoof in which a stranger sends out thousands of e-mail messages intended to trick people into sending personal information, like a bank account number or Facebook password. The message may look like official correspondence from a bank, PayPal or even Facebook. Or it may look like a personal message or a business invoice. The goal is to get you to click your way to a Web page that looks authentic and get you to enter personal information. A Facebook spokesman pointed to the company's help page on phishing, which warns: “Don't click on strange links in posts or messages, even if they're from friends. If it seems weird for an old friend to write on your Wall or send you a message, it's possible that the person's account has been taken over by a spammer.” It also advises to be “especially wary of e-mails that ask you to update your account, tell you to open an attachment or warn you to act quickly before something happens.” In the end, you may have to accept that if you use the Internet, every once in a while, you are going to play the fool.