On Tuesday, the Internet giant unveiled services that will allow publishers new ways to place ads on mobile devices. Yahoo! will sell ads on the Web pages of the business directory Go2, the popular browser Opera Software ASA and mobile video content provider MobiTV.

Yahoo! also announced two new services, Yahoo! Mobile Content Engine and Yahoo! Mobile Site Submit, that will make it easier to locate a site on the mobile Web.

The company also continued to beef up its mobile oneSearch service, a mobile search technology intended to make navigation easier by giving users answers instead of a list of links in return to queries. Yahoo! said it would open up the service to other publishers in order to expand the amount of content available through the service.

Investors should expect more news on the mobile front from the company: "But this is the only the beginning," said Marco Boerries, Yahoo!'s executive vice president of connected life, in a statement. "Opening Yahoo! oneSearch to the universe of mobile Internet content and services provided by other publishers will give consumers even more instant answers and information right at their fingertips."

The moves continue the aggressive build-out by Yahoo! of its mobile platform, where the company thinks it has an edge over rival Google (YHOO - commentary - Cramer's Take). Earlier in March, Yahoo! announced that oneSearch, the keystone to its mobile efforts, was available on 85% of mobile phones in the U,S. The company launched the service in January.

Yahoo!'s mobile service counts 7% of mobile users as customers, compared with 4% for Google, according to the research firm M:Metrics.

Shares of Yahoo! were recently off 11 cents to $31.53.