Google engineers have shared interesting information about the number of pages indexed by search system. According to their data, recently this number had crossed over 1 trillion (1000000000000) unique pages. As it reported in Google blog, the actual number of indexed pages is much more, but many pages are automatically generated copies of others and their contents are the same. These pages Google doesn’t count.
It’s interesting that in 1998 Google had started with a fixed size of the database, which included 26 million pages. In 2000 this number had increased to one billion. Today, Google updates its list of indexed pages constantly, several times a day.