Nielsen today posted its lists of top digital properties for 2011. No big surprises: Google was the most visited site, Facebook the most popular social network and YouTube the No. 1 video site. When it came to smartphone makers, Apple led the way thanks to the iPhone. With Facebook trailing Google in monthly traffic by only 16 million visitors (153.5 million versus 137.6 million), it will be interesting to see whether the social network can overtake the search giant as the top site in 2012. The full lists are here.