Wikipedia defines a proxy server as "a computer that offers a computer network service to allow clients to make indirect network connections to other network services. A client connects to the proxy server, then requests a connection, file, or other resource available on a different server. The proxy provides the resource either by connecting to the specified server or by serving it from a cache." Wordnet has a more general meaning: "a person authorized to act for another".
Google is a supercomputer that performs a set of actions for its users or on behalf of its users.
Google is a proxy for the web
* find information on the web
* view the cached page that contains the information, even if the site is unavailable
* view the page on the mobile phone, even if it's not suited for that medium
* view Office documents, PDF files, PostScript files, even if you don't have Microsoft Office, Adobe Reader or GhostScript
* Google Web Accelerator fetches web pages in advance to improve the speed of your web browsing
Google is a proxy for businesses
* with Google Checkout, you don't have to worry about disclosing sensitive information about your bank account to untrustful merchants
* through Click-to-Call, you can talk to companies free and anonymously using Google proxy
* you can sell products even if you don't have a site, using Google Base and Google Checkout
Google is a proxy for your life
* Google Desktop keeps track of all the web pages you visit and all documents you had on your computer. So it's a great complement for your memory
* Google News shows the news through different lenses so you don't lose your critical thinking
* Blogger is a mirror of things that were important for you. I use this blog as a complex bookmarking system for great software, interesting websites and news that made a difference
* your conversations are searchable through Gmail, Google Chat and Google Talk. Everything you say can be used. It's more accurate than your pictures.