SPEWS is a list which several Mail engineers, and ISPs have assembled and use to block spam emails. This personal long list is currently available for the general public to look at and use for email filtering.
Most spam location systems work after the the spam came in. There is a timeout between the bad actor starting up shop, sending bad email to countless people, and getting blocked in the database with these systems. SPEWS hones in on known bad actors and spam origins, it stops them when they start, occasionally right before they begin sending bad mail.
email security discovered that a number of the several popular spam lists and blocking systems have become bogged down because of an too many requests, this reduces their effectiveness. SPEWS doesn't run A petition or vote based database of spam, entries in the record come from the wisdom and expertise of the people who set up and use the SPEWS list.