More than half of those surveyed in a Ponemon study backed by Internet security firm PC Tools indicated they would reveal mobile phone numbers, email addresses or other information when told they might get something for nothing.
"Even in scenarios where people realize it is too good to be true, they are falling for it," said PC Tools senior manager of online strategy Eric Klein.
Cyber crooks have long exploited human nature with scams relying on "social engineering" to get people to reveal secrets such as passwords or unwittingly install computer viruses.
Manipulations can range from telling people they will be entered in prize drawings after filling out detailed surveys or getting them to open booby-trapped files said to contain sexy or pornographic imagery.
"The results found a clear difference between how aware consumers think they are of scams and how likely they are to be taken in by the given scenarios," Ponemon Institute researchers concluded.
"It is clear from the findings that the threat posed by scams is still being underestimated."
Scenarios people fell for included offers of supposed free anti-virus computer software and get-rich-quick opportunities, according to Ponemon.
People were particularly susceptible when ploys were baited with promises of chances to win tech prizes such as mobile phone ringtones or tablet computers.
"People in the United States were, frankly, more cheap and looking for something to get out of it," Klein said.
"The idea of getting rich made them more likely to put security aside," he continued.
Versions of the study were also done in Australia and Britain; with Australians being unlikely to fall for ploys while British Internet users were more susceptible but far more wary than those in the United States.
Tablet computers made particularly strong lures in all three countries, according to surveys.
"Whenever those gadgets are being hyped they are trendy things to have," Klein said. "People interpret it as status, so they will go to great lengths to get one."
The holiday season brings with it increased chances for online scams as people hunt for gift bargains and cyber crooks expand arsenals to include false offers of tremendous deals on hot items.
"It is really about tricking people into giving up information," Klein said. "Some of the data is pretty alarming."
People were advised to check for secure "https" website addresses for transactions and to watch for misspellings that could signal a ruse.
Klein recommended avoiding websites with addresses in Eastern Europe, particularly Russia, due to the number of scams originating there.
"Take your time, double check what site you are on and look for hints they are not legit," he said.
"Before you give out any personal details make sure it is a real offer."
