About P4P -- although letting the government spy on records is not necessarily a good thing. I do think the ability of the chart to track data, collect statistics and let ME practice to the standard of care by telling me when a diabetic has not had labs, when a child is due for a well child, etc is great. I think that adding these features for me is the next natural step for an EMR.
In regard to the vaccine registry - I as a parent was quick to put my child's records in - if a paper chart gets lost in a fire, if the school has flood damage (recent NW storms did lots of damage) or whatever I can reconstruct their vaccine records in about 3 minutes on the Net. I even know adults who had to redo vaccines just because they could not prove when they were done for college, employment, etc.