A three-fold increase in subscribers and the addition of 13 racetracks helped Youbet.com increase revenue and cut losses during its second quarter.As of June 30, the California-based online wagering business reported having 17,200 subscribers, up from 5,700 at the end of 1999's second quarter. Handle for the quarter rose 110% to $26.3 million compared to the second quarter handle for 1999 of $12.5 million. Youbet.com's revenue for the second quarter jumped 105% to $1.5 million, up from $733,000 during the same period a year ago.The company is still losing money, but at slightly slower rate. The net loss for the quarter was around $3.3 million or $0.17 per share compared to the second quarter of 1999 when net loss was $4.3 million or $0.28 per share. Net loss for the first six months of the year edged upward to $6.7 million up from $6.5 million for the first six months of 1999, but per share losses for the same period improved to $0.35 per share from a loss of $0.44 per share a year ago. Youbet.com received a one-time $6.9 million boost for the quarter when it retired $18.95 million in debt at a cost of $9.9 million. The gain from the retired debt actually put the company in the black by $532,847 for the first six months of the year.