I'm a historian, so Google is most important because I couldn't possibly do research without it. Wiki is helpful in getting basic data (i.e., dates, surround) but Google leads me to the multiple resources I need to do good scholarship. I use YouTube only for watching a few how-to videos. Not interested in Facebook at all.
Ntra la porta tua lu sangu � sparsu, E nun me mporta si ce muoru accisu... E s'iddu muoru e vaju mparadisu Si nun ce truovo a ttia, mancu ce trasu.