Updated from 3:58 p.m. EDT

Google

(GOOG) - Get Report

quietly added video search to its sprawling array of search applications Thursday. The move may seem insignificant, but it is one of those flaps of the butterfly wings that can ripple into much bigger change.

As one of its many research projects, Google has been adding videos to its library from C-SPAN, PBS and several Bay Area affiliates of national networks into its search database. On Thursday, it issued a call for video uploads on its blog, raising the curtain on a kind of open-source donation of videos into its database.

On the one hand, Google's initiative could simply take all those cable-access programs that very few people want to watch and open them up to the entire world -- where very few people will want to watch. (Imagine a gallery of all those "American Idol" rejections.)

On the other hand, it could extend niche videos to the masses, connecting hard-to-find content with specialized audiences hungry for it. Like a TiVo on steroids, video search could turn the Internet into a compelling, customized alternative to television, where viewers are spoon-fed what executives decide to give them.

Just as significant, Google says it's going to be selling some of the videos that its search results deliver up, taking a yet-to-be-determined share of the revenue. With this tiny step, Google is moving away from being purely a search company that makes money from ads and toward an e-commerce company peddling content.

"Eventually your work will be included in Google Video, where users will be able to search, preview, play and purchase it," reads an open call for submissions on a blog that Google maintains. The interesting word here is "purchase." It's perhaps the first signal Google has ever given that it would sell content through its Web site. That could turn into a major nightmare for

Amazon.com

(AMZN) - Get Report

and e-tailers that focus on entertainment content.

A Google spokesman confirmed that the company would be sharing in revenue of videos on its site, but declined to say whether it would be selling other forms of content that are accessed through its search engine.

Yahoo!

(YHOO)

has offered a video-search function for a while, one that scours the Web for sites that already have videos on them. Kathryn Kelly, a Yahoo! spokeswoman, says that Yahoo! Search contains videos from

Bloomberg

and BSkyB and that the site has been soliciting videos through RSS feeds for a while. Yahoo is not yet earning revenue from its video search.

Typical of the epic game of one-upmanship that has been going on between these two companies, Google's video search has a twist: It can search closed-captioning tags, allowing people to drill down into videos the same way that Amazon's A9 engine searches individual pages inside books.

Like many of Google's recent innovations, the video search is in beta. None of the videos in Google's database can be viewed yet, but the site gives some hint of what is coming. A video search on "iPod" brings up 256 results, with the results typically showing excerpts from the closed-captioning transcript and accompanying still images.

The Google spokesman said the company will be sifting through the submitted videos and eliminating those with pornographic or obscene content. Google has not yet settled on guidelines on which videos are omitted from its database. But in asking for and picking among videos, Google is taking a more active role in selecting which content searchers can find.

Shares of Google closed Thursday's regular session down $1.48 to $191.45.