The primary effect this has had is that we now get a ton of single-ring calls which when you pick up, there isn't anybody there, because the NoMoRobo service has already picked up and ditched the call for me. As long as I sit and wait for the _second_ ring, it's like no one called at all. There's probably a setting on my phone to make the first ring silent; I may research that at some point.
Secondarily, when a call _does_ actually come through without callerid info or just a number, there is usually someone real there. Today, it was the Burlington Mall Rainforest Cafe calling my six year old daughter, to see if she wanted to have breakfast with the Easter Bunny. I will ask her when she gets home.
I don't know at what age I expected to start taking phone messages for my daughter, but I think this was a little younger than I had anticipated.