CHICAGO - Nate Silver quit his $55,000-a-year financial consulting job in April to play Texas Holdem poker.

So far it's been a wise career move: The 26-year-old Silver expects to make more than $100,000 this year playing the card game, mainly on the Internet.

Silver belongs to a new generation of Texas Holdem poker players who feast on the growing number of novices taking up poker after watching televised contests.

While few players go to the extreme of quitting their jobs, many spend their evenings stalking sites like PartyPoker.com and PokerStars.com, pocketing an extra $20,000 or $30,000 annually on top of their regular salaries.

And as more novices keep appearing, opportunity grows for experienced Texas Holdem players.

"You'll see people make terrible plays routinely," said Silver, who lives in Chicago. "For the most part these people call too much and play too aggressively."

Online poker has exploded along with the recent surge of interest in the game.

In January 2003, $11.1 million was wagered on the major poker sites. That number rocketed to $136.1 million in September, according to PokerPulse.com, which tracks activity on 21 of the largest poker sites.

Total gambling at poker sites will easily clear $1 billion this year, based on PokerPulse's figures.

People trying to bank quick online profits are reminiscent of another recent Internet phenomena: day traders.

Rather than making rapid-fire stock trades online, these gamblers seek profits by leveraging small advantages with their poker experience, discipline and statistical savvy. While their gains and losses vary widely day to day, experienced players say the odds are heavily in their favor in the long run.

Still, the easy money could quickly disappear if the poker fad fades.

Mike Kim, who lives in Chicago, said he plays online poker every day, sometimes for a couple of hours and sometimes for 12 hours straight. He said his average winnings are $15,000 a month.

"I had no idea it would become my full-time job," said Kim, who started playing online nearly a year ago while studying mechanical engineering at the University of Illinois. "I didn't find a job when I graduated so I just kept playing for money.'

Neal Salmen, a 28-year-old Chicago real estate investor who said he has made about $25,000 this year playing online poker, said the anonymity of Internet games often makes new players more aggressive. In casinos, Salmen said, "You don't want to look too stupid so people play more conservatively."

Internet poker offers experienced players some advantages, particularly the ability to play at several tables at the same time. Online games generally go faster than casino games, and by playing three or four tables simultaneously, players can easily participate in more than 200 hands an hour.

The main disadvantage of Internet play for poker pros is the inability to "read" competitors - noticing small ticks and other mannerisms that can reveal if somebody is holding a strong hand or bluffing.

"It's hard to read someone if they don't know if they have a good hand," said Jim Karamanis, a Chicago attorney who plays recreationally.

Nobody tracks how many people play poker for a living, but the number appears to be growing.

"Certainly at this point there are thousands," said Greg Raymer, who left his job as a patent attorney at Pfizer Inc. after winning $5 million this year at poker's biggest event, the World Series of Poker.

To prosper at Internet poker, players must be technically strong and quickly assess the thousands of scenarios that arise - betting aggressively on strong hands and folding when they're in a weak position.

Signing on to EmpirePoker.com one Tuesday afternoon, Silver put $1,000 into his account and folded most hands before the first round of betting, losing his $15 ante. On the first hand he played, Silver lost $170.

"If I lose $170 on a hand, it's nothing," Silver said. "You can't let it get to you."

Silver usually plays Texas Holdem on weekday evenings and sometimes stays up until sunrise so he can play against aggressive Scandinavian players.

Silver said he's done much better financially with online poker than he expected, though he and other players acknowledge their profitable poker days may not be long-lived.

"I'm just trying to ride it out," said Kim. "If poker starts dying down, I'm going to have to get a real job."