Why Adam gets more spam than Eve

Email addresses that begin with letters towards the start of the alphabet get more than their fair share of spam, says Richard Clayton at the University of Cambridge.

He looked at more than half a billion emails that arrived at one UK ISP over an eight-week period. After ignoring addresses that appear to be out of use, he showed that for those beginning with A 30% of messages are spam. Someone with an address starting with Z gets a smaller proportion - 20%.

The exact reason for the difference is unclear. Clayton thinks it is down to spammers attempting to guess addresses. There are few real addresses that start with Z compared with those that start with A, so guessing them correctly is less likely.

Clayton did not perform statistical tests on the significance of his results. But it is interesting to see that some letters got even more spam than 'A', despite their being fewer addresses beginning with those letters. Those beginning with R, P, S and M all received around 40% spam.