The sign-up phase for launched Thursday. The service itself will kick off in Portland, Ore., according to Google, and roll out in due course to three neighborhoods in Manhattan, San Francisco and the East Bay.

The sign-up page asks people in other places to register their e-mail address and Zip code, and promises discounts of 50 percent or so "for places you'll love" to shoppers and targeted marketing to "high-value customers" to businesses.

Looks like a TV campaign is in the offing, too, since a 60-second spot is up on YouTube, answering the question "What Will Google Offer?" with rainbow-colored images of cupcakes, smart phones and hair dryers. .

The move is no surprise. After Google's $6 billion offer for Groupon was rebuffed back in December, the Mountain View behemoth basically said, "Hey, how hard can it be?" and announced their own deal program in January.

Making it harder, of course, is the ongoing stampede of other companies into the local-deal arena, including local media powerhouses like Media News Group and Gannett, heavy hitters like New York Times and Facebook, and a million look-alike startups like (for restaurants, natch) and (for dentists). Take a look at the trade site for an idea of how insane this field has become.