The Internet has spawned a whole new language and brought the world to your living room or office, 24/7/365. And while the opportunities online for consumers are almost endless, there are some challenges, too. As in dot con. Yes, dot CON.

Con artists have gone high-tech, using the Internet to defraud consumers in a variety of clever ways. Whether they're using the excitement of an Internet auction to entice consumers into parting with their money, applying new technology to peddle traditional business opportunity scams, using email to reach vast numbers of people with false promises about earnings through day trading, or hijacking consumers' modems and cramming hefty long-distance charges onto their phone bills, scam artists are just a click away. Fortunately, law enforcement is on the cyber-case.

Using complaints to Consumer Sentinel, a consumer fraud database, as their guide, law enforcement officials have identified the top "dot cons" facing consumers who surf the Internet, as well as many of the fraudsters behind them. In addition to putting many online con artists out of business, the Federal Trade Commission, the nation's chief consumer protection agency, wants consumers to know how not to get caught in their web.

According to the FTC, here's what online consumers are complaining about most:

1.Internet Auctions

The Bait: Shop in a "virtual marketplace" that offers a huge selection of products at great deals.
The Catch: After sending their money, consumers say they've received an item that is less valuable than promised, or, worse yet, nothing at all.
The Safety Net: When bidding through an Internet auction, particularly for a valuable item, check out the seller and insist on paying with a credit card or using an escrow service.

2. Travel and Vacation

The Bait: Get a luxurious trip with lots of "extras" at a bargain-basement price.
The Catch: Consumers say some companies deliver lower-quality accommodations and services than they've advertised or no trip at all. Others have been hit with hidden charges or additional requirements after they've paid.
The Safety Net: Get references on any travel company you're planning to do business with. Then, get details of the trip in writing, including the cancellation policy, before signing on.