SANTA CLARA, Calif. -- Travel search engine SideStep said it has signed both new and expanded marketing agreements with six major car rental providers: Dollar Rent A Car, Enterprise Rent-A-Car, Thrifty Car Rental, Hertz, Payless Car Rental and EZ Rent-A-Car.

Key campaign elements will include targeted advertising, special offers within search results on both the SideStep.com Web site and the SideStep toolbar, e-mail marketing and featured travel bargains.

"We aim to stay close to our customers, and SideStep helps us to achieve this by encouraging more consumers to use the Enterprise.com site," said Scott Shuler, assistant vice president of Enterprise Rent-A-Car.

"SideStep offers us marketing programs that deliver high volumes of valuable customers," added Charlie Coniglio, Dollar Thrifty Automotive Group's staff vice president of e-commerce.

Online search advertising is positioned for significant growth. Industry analysts predict that U.S. online advertising will grow 53% from $11.5 billion in 2005 to $17.6 billion in 2008. Total advertising in the U.S. is expected to grow 10% from $278.5 billion to $307 billion for the same period. Comparatively, paid search is projected to grow 37% in 2005 alone, from $3.5 billion in 2004 to $4.8 billion this year.