SPAM is the process of sending out several copies of the same email message to many users who may not wish to receive these. This causes flooding on the Internet with many copies of the same message. It is a common form of commercial advertising for many get-rich-quick schemes, quasi-legal services or products of doubtful origin and quality. The SPAM messages can be sent out at very little cost. The receivers may end up paying the cost or it is borne by the carriers.

Judgement sample is a non-probability sample, where the respondents are picked from a group of people who have certain perceptions, attitudes and judgements about the subject under consideration.