SAN FRANCISCO ? Web 2.0, the buzzword coined by O?Reilly Media to describe the explosion of mass interactivity online, is evolving into something new and different.

Tim O?Reilly, the Sebastopol tech trend-setter who helped turn Web 2.0 into a pop culture concept, signaled Tuesday he might soon be ready to retire the buzz phrase.

During his keynote at the annual Web 2.0 Expo conference, O?Reilly described how Web 2.0 technologies increasingly interact with the world through the use of sensors. Cell phones, for example, are equipped with GPS that can share your exact location with your Facebook friends or Twitter followers.

O?Reilly said the interplay of computer sensors and Web 2.0 technologies such as social networking is only growing, and he proffered a tag for this next iteration of the Web.

?We?re calling it Web squared,? he told the audience, a collection of several thousand geeks at Moscone Center in San Francisco. ?We are starting to see a coordination of these sensors. That is the future.?

O?Reilly introduced the new phrase with this equation: ?Web 2.0 + world = Web squared.?

O?Reilly said he had been working on the title with Marin County resident John Battelle, who is founder of publishing company Federated Media.

O?Reilly Media helped make the phrase Web 2.0 popular after one of its original employees, Dale Dougherty, coined it in 2004.

?I simply came up with a name to designate that there was a new beginning ? new energy, new ideas, new approaches to problems ? after the dot-com bust,? Dougherty told The Press Democrat in 2007. ?For me, Web 2.0 was a re-affirmation that the most amazing and innovative technology at hand was the Web, once again.?

Now the most amazing and innovative technology at hand is the Web, the world, and all the sensors interconnecting the two, O?Reilly said.

He described an Internet-connected sensor designed by a college student that automatically Twittered people anytime their plants got too dry and needed watering.

The four-day conference, co-produced by O?Reilly Media, covers far-ranging topics from Internet security to effective use of Twitter by business owners. About 8,000 people registered to attend this year?s conference, which was down a little more than 20 percent from last year.

One session that drew big crowds was a presentation on how businesses can use Twitter, the micro-blogging service that has exploded in popularity.

In a whirlwind tour of Twitter strategies, author Sarah Milstein laid out guidelines for using Twitter and shared a heap of good Web sites.

When starting a Twitter account, a business needs to determine who within the company will run it, said Milstein, who co-authored ?The Twitter Book? with Tim O?Reilly. She suggested it be someone well-connected within the company, who knows how to direct customers to the right people.

?It needs to be someone who can act a little bit like a switchboard operator,? she said.

Also, she shared some examples of companies that created effective promotions and contestants, and used Twitter to generate buzz and spread the word.

She said businesses should not always twitter about themselves, but also share information that is related to their expertise ? in effect becoming a conduit of interesting industry information.

The top Twitters post about 22 times a day, compared to 4.5 times a day by average users. But Milstein suggested that nearly two-dozen posts were too much, and suggested a post a day as a minimum.

Rather than trying to build up a large following of people who don?t care about your tweets, businesses should try to get followers who really want to hear what they say.

You can reach Staff Writer Nathan Halverson at 521-5494 or nathan.halverson@pressdemocrat.com. Check out his blog at DailyGeek.Pressdemocrat.com or on twitter.com/eWords