Remember "Surf's up?"

That was the call. "Surf's up!!" and you dropped work, dropped school, blew off boyfriends and girlfriends, bagged your life, grabbed your board and went surfing.

Twenty years ago, no one used to know when a swell was coming, so "Surf's up!" was the battle cry.

Now you don't hear "Surf's up" anymore because we have the Paul Revere of surfing - Surfline.com.

This year, Surfline turns 20 years old, and over those two decades, it's become the world's most widely used surf report and forecast service.

More than 60,000 people visit the site every day, and its revenues have tripled since 1999, according to the company. The site has the Internet's largest surf camera and report network, with 100 international surf cam locations. In 2001, Surfline came out with LOLA, its fee-based computer-generated surf-forecasting tool that can tell you what's going to happen, anywhere, 10 days in advance. You can even get content on your cell phone.

To celebrate, Surfline is doing Surfline 20, a series of articles run each month on the site such as "The 20 Greatest Swells Since 1985," and "The 20 Best Reader-Submitted Photos."

Surfline "kinda started as a passion, really, or a hobby because I grew up sailing but surfing was my passion," said Surfline president Sean Collins in a phone interview from his office in Huntington Beach.

When Collins, 53, was a young surfer in the '70s and early '80s there "really was no forecasting at all," he said. "It was really like the Dark Ages."

Using a short wave radio and middle-of-the-night reports from New Zealand, combined with his own growing body of observations and data collection, Collins was able to jury-rig a system of forecasting that he tweaked and improved over the years. He eventually added civilian weather information from the Navy that he could further refine.

"By '84 you could see there was obviously a pretty good need (for surf forecasting), and there was no one doing it at all," he said.

Previously, many had believed that accurate surf forecasting, especially for waves generated in the South Pacific, was physically impossible.

He and a few other guys and started a phone service, 976-SURF, in 1985, for 55 cents per call. The service, started in Southern California, spread to Northern California, then went nationwide. Then came fax machines, then the Internet, and Surfline.com was born in 1995.

The beach cam idea took off, though it didn't make money at first.

"That was kind of a nightmare because no one had really done that before, and it had to be stable," said Collins.

In 2000, Surfline was purchased by surf lifestyle retailer Swell.com, which expanded the cam network and helped Surfline develop the information-rich LOLA service. But after the dot-com crash and 9/11, Collins and the other leadership at Surfline decided to separate from Swell. The other owners in the company are Chairman Jeff Berg and CEO Jonno Wells. Surfline now has about 30 full-time employees.

Now, when it comes to surf forecasting, Collins is widely acknowledged as the guru. His expertise helped lead to the discovery of remote big-wave sites including Cortes Bank in Southern California. He consults with contest organizers, movie production companies, pro surfers, corporate executives, lifeguards, government agencies and the Coast Guard. He was named one of the "25 Most Influential Surfers of the Century" by Surfer Magazine in 1999 and the "8th Most Powerful Surfer in the Surf Industry" by Surfer in 2002.

In addition to the surf cam offerings, the site has also become a free encyclopedia and jam-packed surf information hub, as well as a community bulletin board of sorts, with a public photo gallery and localized events, news and notices posted on regional pages.

"One of our big efforts is to create a community forum," said Dave Gilovich, Surfline's marketing director. "We want to make it more of a place where you can interact, where you can come if you've lost your surfboard" and want to post a note to help get it back.

With all the cams and reports and forecasts, some in the surf community grumble about the Internet drawing the masses and ruining surfing.

But Collins says, "it's 2005, it's no longer 1970, you know?"

The market demands it, he said, and the overall surfing community demands it.

"And quite frankly," he said, "if we don't do it there a zillion other people who are going to do it."

Also, Surfline takes pains not to call out individual beaches.

"We could sit here and go, 'Wow this is a great swell for Fullers or Moss Landing or Natural Bridges,' " he said. "We could just kill it, but if we did that we could send a 1,000 people there, and that would be really irresponsible."

So, to the service that changed surfing, happy 20th. Next year, maybe we'll buy you a drink.