document: Surfing the web by site We provide a system for surfing the web at a high level of abstraction , which is an analogy of the web browser , but which displays entire sites at a time . It allows a principled investigation of what is present , based on an overview of all available information . We show a site 's relation to other sites , the broad nature of the information contained and how it is structured , and how it has changed over time . Our current system maintains a continuously updated archive of 40 million sites representing 1.9 billion web pages , and enables real-time navigation through the sea of web sites .
doc_bio_tags: O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O