Learned about an interesting theory today. The idea is that Nigerian payment con artists push emails that are obviously scams (what with all the horrid grammar, funky domains, and still operating out of Nigeria after all these years) intentionally, attracting only extraordinarily gullible users. It is suggested that powerful spam filters are helping the con-artists and that these scams could be rendered less effective by loosening email filters so dumb inexperienced users get better at recognizing spam.

Source: onthemedia.org