Google is a search engine -- it scours the web for the best responses to text queries. It was founded in 1998 by Sergey Brin and Larry Page. Originally, Google used links to determine the importance of webpages, though the service's algorithm has grown in sophistication since then. It is one of the most important search engines in the world and is an invaluable traffic-driver for many sites. Google has expanded into many areas beyond simple web searches, including mapping and directions (Google Maps), video (YouTube), and photos (Picasa). It's also noted for its doodles -- illustrations and interactive art pieces that occasionally adorn the front page of the search engine. In January 2012, Google rolled out "Search plus Your World," which integrated search results from its social media service Google+.