Over the past twenty years, internet scams have gone from shadowy, lurking, cyber threats to the stuff of late night comedy fodder. We've all heard punchlines about Nigerian royalty and online pharmacies by now. We laugh, shake our collective heads, and marvel at how naive and gullible we all were at the dawn of the internet.

The only problem is, many of us are still falling for tricks just as old and obvious as Prince Alyusi Islassis' plea for a quick loan. Here are five scams that are as old as dial-up but still manage to snag the  unsuspecting. 

Many of us like to clear out old junk by tossing it up on a free classified-ads site like Kijiji or Craigslist, and that's not a bad thing. Just be careful if you receive an offer too good to be true. Let's say you list a sofa on the service with a price tag of $100. Can't you believe it, some nice soul in Wisconsin thinks it would look perfect in his living room! In fact, he likes it so much he is willing to mail you a check right away for $600 to cover both the cost of the sofa and to ship it him. All you need to do is deposit the check and send $400 by Western Union to his shipping company.

Sounds like a great deal, you're making more on the sofa than you expected and with the cheque in hand you know you can't be burned. Except you can and will be. Sure, the cheque will look legit, and you'll deposit it, wire him the money for shipping and it will seem like everything is copacetic. Until the bank calls you up to let you know that the money order was a fake and you're left $400 out of pocket and missing a sofa.

Everyone likes to save money and if an offer on a pre-approved Visa card happens to land in your inbox, you might be tempted to follow up on it. I mean, it's a great deal, they're offering a fantastically high credit limit, low interest rates, all you need to do is pay the annual fee to get started.

Well, you can probably fill in the rest from here. 

There are endless variations on this con. It can take the form of a sweepstakes prize, a lottery, an investment, a trip – all of them offering a great windfall you'd love to get your hands on, and all you have to do is pay a small handling fee, shipping, deposit, etc. 

This is a scam that preys on fear and a lack of familiarity with your computer. You're on the internet, doing your thing, minding your business when a pop-up message appears with a dire warning. Your computer is under attack! A virus has been detected! Hackers are working, right now, to get into your private files, accounts, and personal information. 

But don't worry, for just $25, "Windows security” (or whatever name they've cooked up) can quickly install an anti-virus program that will repel the attack and protect you next time.

Or more likely, take your money and install a ton of malware on your PC. 

"Help me, I've been mugged!”

This particularly devious scam might just get the better of you if you're not watching out for it. It takes advantage of our loyalty to friends and family by masquerading as a loved one in a tight spot.

"I'm in big trouble, man” the email begins "I'm stuck in Vancouver. Some guys stole my wallet, my money, and my cell phone. Thank God I kept my Passport and ID in my other bag. But they got my tickets, I can't pay the hotel, and I haven't eaten all day. Could you wire me some money so I can get home? I'll pay you back as soon as I land.”

Weird, I didn't even know Frank was in Vancouver! But it must be him since it was sent from his email...

Wrong. The reason this scam works is because your friend has been infected with some kind of malware that has given scammers access to his address book. They're either in his email or Facebook profile and have sent the same story to anyone who seems close enough to him to be more concerned with helping a friend or relative out of a jam than taking the time to confirm the details of the situation.

Get in contact with your friend before sending any money and make sure the story checks out. If by some circumstance you can't get a hold of them by anything other than email or messages and you're not sure if you're talking to the real deal or not, ask a question only that person would know.

Have you noticed a pattern with these scams? They all rely on you being too excited to think clearly. With either the promise of a great deal/free money, or fear for yourself or a loved one, they want your hands to reach for your credit card before your brain can say no. The best defense to all of these scams and their multitude of variations, clones, and copy cats is to just think about what is going on before doing anything.

Any unsolicited request for money, no matter how elaborately concealed or downplayed by some devious distraction, is likely a scam. If something seems too good to be true, or is pushing you too hard to act immediately, it's best to just walk away. Don't let your blunder today become the punchline of tomorrow.