It’s pretty easy to get ripped off in the physical bricks-and-mortar world if you’re not careful. It’s no different in the digital world online.

Some scams are so bald-faced and clumsy that you marvel that anyone still falls for them. Others have a reasonable patina of plausibility that can seduce the unwary.  Unfortunately, there’s no real-world correlation between technological savvy and street smarts. It’s almost embarrassing to have to repeat an old cautionary bromide, but here it goes: If something sounds too good to be true, it probably is.

Keeping that in mind, here’s a run-down of some of the most pernicious online rip-offs as well as one or two that add a new spin to the art of online duplicity.

Nigerian (419) Scam

This one, which plays on greed, is one of the oldest digital rip-offs on the books. You get an email from a wealthy Nigerian (fill in the appropriate country, this one travels well) who needs help in transferring millions of dollars from his homeland. If you are able to assist in the process, the email continues, you’ll receive a sizable cut of the fortune as a reward.

If you take the bait, you will be asked to put up some of your own money to smooth the transfer. It’ll be the last time you see that money or the scammers; there is no fortune that needs to be transferred other than yours. The number “419” refers to the article of the Nigerian Criminal Code that deals with fraud. Any email from strangers that promises riches in exchange your help (read: money) and trust should be avoided. According to scambusters.org, the Nigerian Scam and its cousins still bilk people for between $100 million and $200 million each year.

eBay Buyer Remorse

Buying on eBay can be great fun as well as a source of bargains on a whole cornucopia of goods and services. It can also be a disillusioning experience if you never receive the goods you bid on and paid for, or if what you gets doesn’t live up to the seller’s description. A majority of eBay sellers are legitimate and go the extra mile to maintain their good reputations. In a barrel this large, though, there will be some bad apples. Avoiding them is the best way to not get ripped off.

eBay recommends looking at a seller’s feedback before hitting the buy button. Just click on the seller’s feedback score next to the seller’s user ID. If you’re dealing with a new seller who doesn’t have any feedback or with one who has negative feedback, use the “ask a question” link to communicate directly with the seller.  You should also look at the icons by the seller’s user ID to learn more about them.

Gone Phishing

Identity theft is alive and well online. One of the slicker phishing ploys making the rounds comes in the form of official looking emails claiming to be from a bank, credit card company or site such as Best Buy or eBay asking you to verify your account details and password. The email is generally tricked out with authentic looking logos and authoritative text reassuring the recipient that their security is a paramount concern and includes a link for you to use in the verification process. Don’t do it.

There may be subtle clues that the email is not as it seems, such as the return header containing a Hotmail address. The best clue, though, is that legitimate companies never request this kind of information via email. If in doubt, go to the institution’s official web site by typing its URL in the address bar of your browser, not by clicking on any links in the email you received. The scam may be listed on the home page. If in doubt about the authenticity of the email you received, call or email the institution’s customer support department.

Disaster Scams

Your humanitarian impulses offer rip-off artists an opening to take another shot at your wallet in the wake of well-publicized disasters such as Hurricane Katrina or the earthquake that devastated Haiti. The latest to raise its larcenous head uses the Iceland volcano that grounded flights around the world as its vector.

The fraudsters hack email accounts and start sending emails to that account’s contacts list. A plaintive message is sent out saying that the account holder is stranded because of the eruption and needs money to get home. The recipient is instructed to contact the sender on where to send the money and the message includes an email address that looks like it comes from a Gmail account but is slightly different. A quick phone call can defuse this little bit of skullduggery.

Your Resume Has Come to Our Attention

Remember, stealing your time is as much a rip-off as taking your dollars.  The major job search sites such as Monster.com and CareerBuilder.com do a good job of directly channeling job seekers to appropriate opportunities without inundating them with sales pitches or making them jump through hoops to browse job listings and details.

But there are some that take your job hunt and use it as a vehicle to upsell you to paid memberships if you want access to premium job listings or solicitations to fix your resume for a fee.  Some are notorious for offering personalized critiques that in actuality prove to be formulaic boilerplate based on the keywords you use in your resume. The companies that do this are relentless. The best litmus test for a job search site is this: Does it spend more time steering me to the services it sells or to genuine job openings?

Craigslist Connivers

Craigslist is a wild and wooly bazaar of goods for sale, apartments for rent, jobs listings and meeting people. Because it’s faceless and generally free to use, it also offers safe haven for rip-off artists. Craigslist apartment listings, particularly in large metro areas such as New York City, are well-known hotbeds of fraudulent activity.

You see a listing for an unbelievable rental in a desirable neighborhood at a below-market price.  Because it’s such a great deal and will rent quickly, you’re asked for an advance deposit, even though you won’t be able to see the apartment before forking over your money. You can see where this is going. Fraudguide.com reports that one woman running this scam collected $60,000 in rent and security deposits from several dozen different people. If you’re looking for an apartment on Craigslist, park your trust at the door and do your due diligence.

Fake Anti-Virus Software

Fake anti-virus programs account for 15 percent of all malicious software, according to a new Google study. Computer users are tricked into downloading these programs when a window pops up on their screen telling them that their computer has been affected by a virus. It provides a link to an antivirus program they can download that claims it will cure the problem. It won’t, since there’s no problem to begin with, but it will either steal the user’s data or demand a payment of $40 or more to register the fake product. Sometimes it does both.

The best antidote is to not click anything and close down your browser. Know what anti-virus programs are installed on your computer and make sure they’re up to date. They should already be protecting you.