# Google hits a milestone:

and the web is a very very big place: Google is indexing 1 trillion (as in 1,000,000,000,000) unique URLs on the web at once!

To keep up with this volume of information, our systems have come a

long way since the first set of web data Google processed to answer

queries. Back then, we did everything in batches: one workstation could

compute the PageRank graph on 26 million pages in a couple of hours,

and that set of pages would be used as Google’s index for a fixed

period of time. Today, Google downloads the web continuously,

collecting updated page information and re-processing the entire

web-link graph several times per day. This graph of one trillion URLs

is similar to a map made up of one trillion intersections. So multiple

times every day, we do the computational equivalent of fully exploring

every intersection of every road in the United States. Except it’d be a

map about 50,000 times as big as the U.S., with 50,000 times as many

roads and intersections.