Google has improved their search box. Now when you type into Google it guesses what you’re typing and offers suggestions in real time.
• Helps formulate queries: Instead of just typing [hotels in washington] – did you want [hotels in washington dc] or [hotels in washington state]?
• Reduces spelling errors: Since suggestions are spell-corrected using the same “Did you mean?” feature that offers alternative spellings for your query after you search, misspellings and typos can be corrected ahead of time. Instead of wasting your time with a misspelled query like [new yrok times] or [tomorow never dies], search the first time with the correctly-spelled query.
• Saves keystrokes: Who wants to spend their time typing [san francisco chronicle] when you can just type in “san f…” and choose the suggestion right away?
From the official Google blog.