Updated from 12:41 p.m. EST

It's time to meet TV Guide's newest rival: Google ( GOOG).

On Tuesday, the search-engine phenomenon unveiled the preliminary version of a new service enabling people to search through the content of certain television programming.

While the beta version of Google Video is primitive and its limitations are obvious, it's easy for an outsider to imagine that this first step could lead the way to Google's becoming the television gatekeeper that the company's press-release-hype announces it aspires to be.

"What Google did for the Web, Google Video aims to do for television," Google co-founder Larry Page said in a statement Tuesday. "We are working with content owners to improve this service by providing additional enhancements such as playback."

In fact, Google's entry into video spotlights what one online advertising participant calls a major opportunity for the online search business: the searching of video content, not just text from Web pages and printed matter.

As video-on-demand viewing libraries grow to thousands of hours and increasing numbers of TV viewers use digital video recorders, it is increasingly important for people to be able to search through all that material the way they can search the Internet with conventional search engines, says Jeff Lanctot, an executive at the Avenue A/Razorfish unit of the Internet advertising firm aQuantive ( AQNT).

"When a consumer can do that -- imagine how much video a person might consume," says Lanctot.

The Google Video beta, available at www.google.com/video, may have a promising future. The new search tool promises to hand the company another weapon as it grapples with Web rivals Yahoo! ( YHOO) and Microsoft ( MSFT) for domination of the Internet.

But for now, Google Video's shortcomings are well apparent, as are the possible potholes that lie in the path of Google's actually making money off of the currently commercial-free venture.

In its current version, Google Video enables viewers to search the closed-captioning content of an unspecified number of TV programs that the company began indexing last month.

Entering a query, says Google, will return a list of relevant TV programs with still images and text excerpts of where the search phrase was spoken in the program.

Other features show when a particular program will be aired next, enable searching for specific words within a show, and display program and episode information.

Google says it is indexing television broadcasts in the San Francisco area, some cable channels including C-SPAN, and a PBS national satellite telecast.

As with Google text searches, results can be simultaneously helpful and puzzling. A search for "Google" on Google Video, for example, links to transcripts of a 60 Minutes piece about the company that aired Jan. 2, and a Tuesday mention of Google Video itself from a San Francisco TV station's early morning news broadcast.

But, as closed-caption watchers might not be surprised to learn, some of the content Google links to is garbled and incomprehensible out of context. For example, another "Google" search result is a December airing of a Fox Network show called Ace Lightning -- one that displays the hazards of closed captioning in all their glory.

"Thissn't some kiddie show fojpuppets," read the search results. They continue: R: ren Google this to Chew on, rat! @ Screaming mm, mm! ^Tastes like chicken. Rr get 'Em off me! Get them O me! You ask and googler goes googly! Laughing maniacay @ ahh! Grumbling bntin @ grunting ^that's enough entertainment for now."

Indeed it is.

In its current setup, Google Video doesn't include advertising or playback options for video. With Hollywood and other video copyright holders vigorously protecting their rights, it would seem that Google's display of moving video would involve some serious negotiations -- negotiations in which Google's arguments that the searchability of that video content increases its value would likely bump up against copyright holders' arguments that it is their content that gives value to Google's search of it.

"We are in discussions with a variety of programmers," says Google Video product manager John Piscitello. "We are talking to as many of the content owners as we can to help develop the service further and get consumers connected to video they want to see."

In these discussions, says Piscitello, "We talk about the benefits. ... Users can discover TV shows that they may not have known about, because they contain information they're interested in. ... Just like Google Web search drives users to Web sites, Google Video drives users to show on TV."

Content owners, says Piscitello, "want to be sure that all the rights issues are worked out. And we're working with them, and that's going to be a process that occurs over time."

Another likely point of negotiations is how Google and content creators might split up any advertising revenue Google reaps with that third-party content in the background. Google, notably, hasn't sold advertising on an older preliminary service it offers, Google News -- a news service assembled from third-party content that raises the same questions as Google Video.

"Right now, we're most focused on launching the service, getting feedback from consumers and learning how to improve it," says Piscitello. "This is an early-stage product."

Google's volatile shares, which went public at $85 a share last August and peaked last week at $205.30, fell $2.89 Tuesday to trade at $177.83. The company is slated to report fourth-quarter results Feb. 1.