A year ago the masses had never heard of the iPhone (AAPL). This year, it was the most searched word on Google.

The iPhone ranked tops in both the U.S. and globally among the 10 most searched terms. “It became increasingly popular throughout the year, starting with the announcement in January and continuing on with the release in June,” said Marissa Mayer, Google’s (GOOG) VP of Search Product and User Experience during a press conference Tuesday.

If Google’s Zeitgeist list is any indication of what trends matter to the public, then the presidential candidates should be worried. Along with the iPhone, the top 10 U.S. list included four social networking sites — Webkinz, Club Penguin, MySpace (NWS) and Facebook. The other five included entertainment searches — celebrity news outlet TMZ, Transformers, YouTube, Heroes, and Anna Nicole Smith.

“In search, there’s a lot of interest in celebrity culture, television and movies,” Mayer said. “New terms and new meaning of terms like the iPhone, Transformers and Heroes.”