Larry Page (Sergey's partner) had a grand thought (for the good of humanity of course) that it would be wonderful if there was a database of everyone's medical (collected anonymously of course) where the information could be marshaled to "save 100K lives a year."
13:45 mark of this video:
https://
www.youtube.com/watch?v=mArrNRWQEso
But since the pesky privacy laws were in his way, looks like Sergey's wife did something similar to what Facebook did - just offer a service and simply have people volunteer this information.