Online wagering firm Youbet.com Inc. signed 2006 Trainer of the Year Todd Pletcher to an endorsement deal, the company announced Tuesday. Pletcher was signed in a bid to expand the Woodland Hills-based company’s appeal to younger audiences, the company said. The 21-40 year old segment is the most robust source of new customers, said Youbet CEO Charles F. Champion, in a statement. “A new generation of horse racing fans is discovering our sport online,” Champion said. “Youbet does the best job of taking horse racing to market for this key segment of younger fans and I’m delighted to be working with them to help expand the base and bring new fans to racing.” In January, Pletcher was named Trainer of the Year for the third year in a row at the 2006 NTRA Eclipse Awards/ In 2006, the 39-year-old Pletcher set a single-season purse earnings record of $27.6 million, breaking a 19-year North American record for the most stakes in a year.