SCAM is a term that indicates an attempted fraud perpetrated by social methods. In dating sites the most frequent frauds are said "sentimental" for the sole purpose of obtaining money directly from the victim or by an illicit use of his/her personal data.
The frauds we are talking about generally begin with a contact by the scammer who send you a message in which he/she says to be very interested in you and invites you to contact him/her back.
The ways the scammer uses may be different : he/she sends you his/her e-mail from the very first message or ask for yours, or sometimes invites you leaving Lovepedia to go and use other services as Skype o something similar where he/she feels more confortable and we cannot protect you.
Once he/she has received your answer, it starts a time of mutual exchange of e-mails or messages and after gaining your trust, you will be asked to send some money with a plausibile excuse, such as he/she needs money urgently or he/she asks you for money to travel to meet you or someone in his/her family suddenly needs to be cured of a serious disease: generally you will send the money through a bank account or more often through a money tranfert service such as Western Union.
As soon as he/she obtains the money, he/she disappears. In some cases, however, it can also happens that you do not receive money requests directly, the scammer will use the data you yourself have provided him/her in order to blackmail you or use them to get your money (password theft, etc..).