I interviewed with google last month. I met like ~20 people who were also interviewing at google at the hotel breakfast. Some of them said they have been prepping for the interview everyday for past 4 months ( didn't help with my confidence :)).
Reception at google was filled with 100s of people waiting for their turn to be picked up. And this was just one building among of many, many buildings. Lady at the reception at Avis car rental told me that they get 100's of people coming everyday for interview at google. It was bizzare and surreal to experience 'interview industrial complex' first hand.