Google created a new Web page that explains users why it's a good quality idea to create a Google account. "One name, one password. That's all you need. Its free. Take a look at how you can personalize and optimize your knowledge across all Google products and services."
Using a Google account, you can share photos, track your favorite stocks, get more storage for your email, share your schedule, create web pages and work together on documents, make free phone calls and chat face to face, get modified search results and personalized news, create custom maps and get the same experience on multiple devices. There's a lot you can do if you have a Google account.
While most of the new Google services and skin require an account, back in January 2005 Google didn't have many services that necessary authentication. As the Wayback Machine shows, the initial services obtainable with a Google account were Google Groups, Google Alerts, Google Answers and Google Web APIs, but Google promised that "in the future, your Google account will give access to all Google programs requiring sign in including: Google AdWords, Google Store and more." One year later, Google previously offered Froogle, Personalized Search and a Personalized Homepage and it was preparing to launch Google Calendar, Google Spreadsheets, Google Writely and to obtain YouTube.