Google has been talking about the size of its web index on its official blog this week, as the search engine has reached a milestone of 1 trillion web pages.

This is the number of unique URLs that Google knows of – the search engine does not necessarily make all of these URLs searchable, as they do not always lead to unique web pages.

Still, the figure gives you an idea of how big the internet is, as well as how many pages Google can index.

According to the Google Blog: “So how many unique pages does the web really contain? We don’t know; we don’t have time to look at them all! :-) Strictly speaking, the number of pages out there is infinite…But this example shows that the size of the web really depends on your definition of what’s a useful page, and there is no exact answer.”

There is little benefit to the search engine in indexing every one of these pages, as many are duplicates, or very similar to other web pages.

In 1998, the first Google index contained 26 million web pages, and had grown to 1 billion by 2000. Google used to display the number of pages it indexed on its homepage, but dropped this statistic in 2005.