the main site with free ads in the US, Craigslist, regularly warns consumers of scams. These scams need not be romance-related. There are common threads that people should be aware of. E.g. if an apartment is listed with the rental price below market (by much) and the owner says in the ad that she or he had urgently needed to move to China but would send the keys for the apartment via FedEx to his or her new tenant after receiving a Western Union wire, that is a scam. There are MLM scams. There are work from home scams. There are secret shoppers scams. There are "you have money in a Nigerian bank" scams. There are lots and lots of scams. People are gullible and want to believe what in reality seems to good to be true. This is a general trend and "romance" is a specific example of that general trend. Loneliness, as has been noted above, makes people especially susceptible to romance scams, while laziness or desperation makes them susceptible to scams that promise easy money. The exact reason differs, but the main idea is the same - people want to believe in something that to a neutral and grounded outside observer would appear too good to be true, be it love at first chat message or a windfall of money or an unrealistically good deal on a purchase, etc.