“Google currently processes over 20 petabytes of data per day through an average of 100,000 MapReduce
jobs spread across its massive computing clusters. The average
MapReduce job ran across approximately 400 machines in September 2007,
crunching approximately 11,000 machine years in a single month. These
are just some of the facts about the search giant’s computational
processing infrastructure revealed in an ACM paper by Google Fellows Jeffrey Dean and Sanjay Ghemawat.”

20 petabytes of data is quite a lot of ones and zeroes. . . .20 petabytes is, according to Google, 21,474,836,480.  21 BILLION megabytes processed PER DAY.
That would take 42,950  hard drives of 500 gigs each, which would weight almost 107 tons, 750 pounds.  So thats TONS of data. . . . .

Read more about the type of data, and how much data Google processes, here.
http://www.niallkennedy.com/blog/2008/01/google-mapreduce-stats.html