MOUNTAIN VIEW, Calif. — Google, which recently launched Google Video, its section for user-generated video content, has made a curious change to its upload area warning, striking the word pornography from a page that previously forbade users from uploading “pornographic or obscene material.” The warning now only restricts users from uploading “obscene” material.

Writing for TechCrunch.com, Michael Arrington took note of the quiet policy shift, speculating that the search engine turned portal that has recently reinvented itself as everything Internet could be eyeing the lucrative adult entertainment market.

“Either they’re just testing the boundaries of what their users will allow, or [they’re] in the middle of making changes that could allow more hardcore content,” Arrington said. “Either way, porn is big business, and I’m sure Google has thought long and hard about how to get their piece of it.”

Despite Arrington’s hypothesis, Google hasn’t exactly decided to work blue. The company’s terms and conditions still prohibit the use of pornographic material. Users also must still certify that their content is not pornography in some areas of the site such as the “edit video” area.

In the meantime, Google does allow users to classify their content as “mature and adult.” A number of posts under the “mature and adult” heading lead to videos containing nudity. While the videos do not contain hardcore elements, they could arguably be called porn insofar as the combination of eroticism and nudity seem to be designed to titillate the viewer.

A cursory XBIZ search returned no hardcore results on the Google Video site. But one result, an ad by porn star Peter North for Maximum Pills, demonstrates that the model of porn and profit could be a viable mix on Google.

Google’s decision to launch its video service comes against the larger backdrop of what many observers are calling a new Internet trend. According to Nielsen NetRatings, five of the 10 fastest-growing sites on the Internet are driven by user-generated content.

"User-generated content sites have seen significant growth over the past year, owing in large part to their reliance on viral marketing," Nielsen NetRatings director of media analytics Jon Gibs said. "They also benefit from their cost-effectiveness — the content is practically free."

According to Gibs, MySpace, which pulled in 46 million unique users in July alone, seems to be the site to beat. The site grew by 183 percent in the last year, compared to Google, which posted a comparatively modest growth rate of 23 percent.

While YouTube did not appear in the top 10, Gibs said, Nielsen believes it is the leading contender to unseat MySpace in the coming year.

Not surprisingly, adult webmasters have taken notice, publishing sites such as XTube.com, which are designed to mimic the YouTube experience with a porn bent.