It was followed by other technological phenomena that made headlines this year, including the viral video chat site Chatroulette at No. 2, Apple's iPhone 4 at No. 3 and Facebook at No. 7.
"What we're seeing in 2010 in the U.S., based on our look at the top-rising queries, is really that technology is a really big theme," said Jonathan Effrat, a product manager on Google's search team. "It's really taking off compared to last year."
Twitter may have topped the list last year and Facebook ranked number 3, but this year's list shows that interest in technology has really ballooned, he said. Even the sole celebrity to make the list -- teen idol Justin Bieber (who ranked fifth) -- started out as an Internet sensation.
The World Cup, which grabbed the fourth spot on the list, made Internet history of its own by breaking records for Internet traffic and live streamed video views.
Effrat said it's not just technology that emerges as a trend in this year's zeitgeist but, in particular, the social Web and mobile technology.
"For many years now, it seemed like mobile was on the forefront. This is the first year that we've seen that reflected in the searches," he said.
Here's the full list of Google's fastest-rising searches for the U.S. in 2010:
1. iPad
2. Chatroulette (social website that pairs strangers for videocam chats)
3. iPhone 4
4. World Cup
5. Justin Bieber
6. Myxer (free ringtones, MP3s, wallpaper)
7. Facebook
8. Grooveshark (Internet radio site)
9. Glee (Fox TV show)
10. Mocospace (popular mobile social network)
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