I block them or let them go to the machine, and they never leave a message. The few times I have picked up, no one answers. I assume one person is monitoring many phones, and if they just got a 'live one' my answer is missed. Hmmm, although that has happened enough it makes me wonder - if they are missing 90% of the people who pick up, what's the point?
Another 'plug' for NOMOROBO, works with any phone system that has a 'simultaneous ring' feature (just enter one of the other companies to get through the sign up).
I see they have updated the list, my VOIP 'Phone Power' is on it now, it wasn't before, I just said I was with AT&T (I think that was it), and they enable you. You just need to know how to set up your system for simul-ring to the number that NOMOROBO supplies. They look up the call in their database, and hang up if its a spammer, it drops the call on your end as well.