Google's New Ad Effort Could Take Time; Move Into Display Advertising; Company looks to repeat its success with text ads, but Yahoo has head start.(INTERNET & TECHNOLOGY)

Byline: PETE BARLAS

Investors shouldn't expect Google to display a new source of revenue soon.

The popular Internet search engine is getting into the realm of display advertising -- visual online ads, such as banners and videos.

But Google likely won't show significant sales from the move for at least a year, say analysts.

The company will need to work out operational issues and technical glitches before it can hope to get a meaningful slice of the billion-dollar display ad market, they say. Google is starting from scratch with display ads, while Yahoo and others have offered such services for years.

"The central issue is that Google hasn't had any display ads on its site and Yahoo already does," said Greg Sterling, analyst for the Kelsey Group, a research firm.

Google, which is highly …