When you go out door to door for a candidate, I have, you get a list thats even more detailed. Who votes in primaries, who only votes in general elections, party affiliation name, key interests.
It really helps. If you are in a primary, and see a person who has voted in 2 previous, you can bet that they will again. So, you go talk to them. Or ask to sign a petition.
You can look up the data yourself too... it is public record, and if your neighbors like to tell you all about thier political views but havent had the drive to take 5 minutes and push a few buttons.. then they really should stuff it.