My yahoo mail is saturated with spam. This is because I only use it for sign-ups.

The spam is so bad in the time it takes me to navigate from the sign-up site to the yahoo webmail box, the 'confirm email address' message is usually beneath 20-30 spams.

My gmail is clean.

My university email account is spammed rather heavily, my theory is that some programmer made a program that attaches random combinations of letters and numbers to the domain name my university uses.