Google is facing mounting protests from newspaper publishers in Europe, the impact of which could ultimately affect the amount of content available to end users through search engines.

The company is due to appear in court on Friday morning to do battle with the Belgian press, which filed a lawsuit earlier this year accusing Google of copyright infringement for the way it posts headlines and snippets of their news stories on Google News.

Meanwhile, in the past two weeks trouble has also stirred up elsewhere. The company was forced to put on hold the launch of its Google News Web site in Denmark last week after newspapers there demanded a system that would allow them to "opt in" to Google's service, rather than having their content trawled automatically, said Holger Rosendal, head of the legal department at the Danish Newspaper Publishers Association.

And a Norwegian media group has written to the search giant, objecting to the way that Google posts thumbnails of its members' news photos. "According to Norwegian copyright law, you are not allowed to use photos without permission from the rights holder, so that's the big issue here," said Pernelle Borset, associate director of the Norweigan Media Businesses' Association.

The protests highlight mounting concern among some publishers that Google has gone beyond a simple search service to become a powerful media company that profits from the content of others. Publishers of news, books and other content types have filed lawsuits, often charging copyright infringement, to force Google to seek permission before using their work and even provide them with compensation.

Google responds that it acts within the law because it posts only snippets of publishers' content, and because the publishers can opt out easily. It notes that it drives traffic to publishers' Web sites, since it links to their publications, and it can help publicize works that might not otherwise be found.

Moreover, it says, if search engines were forced to get permission from every site they indexed, search services would not be able to operate at all.

"If content isn't indexed, it can't be searched. And if it can't be searched, how can it be found?" asked David Eun, Google vice president for content partnerships, in a Google blog post. "Imagine a library with no index of titles or subjects of the books on its shelves, or no catalogue of the authors who wrote them."

But that, critics say, is the point. Google is not a public service like a library, it is a profit-seeking company. Google may not "aggressively monetize" Google News with advertisements, but the site attracts visitors to Google, and visitors mean money.

"The exceptions (for fair use) don't really cover what is in effect a commercial service, and that's where they are vulnerable," said Laurence Kaye, a lawyer in the U.K. who is advising the newspaper industry on copyright issues.

Google isn't the only company targeted. Copiepresse, the group representing Belgian newspapers, also sent a cease and desist letter to Microsoft's MSN division, which promptly removed the Belgian newspapers from its Web site rather than become embroiled in a lawsuit. Copiepresse has said that it may sue others.

The outcomes of the various lawsuits, also brought in the U.S. by Agence France Press, the Authors Guild and others, will shape how Google and other search engines can index and display copyright material on their Web sites. For users, they will determine whether search engines continue to give them easy access to such a wide variety of content.

Google lost an initial ruling against Copiepresse in September and was forced to remove the newspapers' content from its Belgian search site and from Google News. Google was not present at the hearing, however, apparently because of an administrative error on Google's part. On Friday -- assuming it shows up -- it will defend itself for the first time.