The dispute that broke out last week over Google's latest attempt to promote its Google+ social network marks growing frustration among internet competitors about the way the search company gives preferential treatment to its own services in search results.
Despite indications that regulators will study the latest move, however, some rivals warned that the U.S. has been slow to pursue its investigation of the wider issue and that Google's persistence with the tactic has allowed it further to reinforce its search dominance.
Google last week added a greater degree of personalization to its search results by injecting content from its Google+ network for users who are signed on to the network. The feature, called "Your World", drew complaints from Twitter, whose tweets are not included in search results in the same way.
The dispute echoes a series of complaints over earlier Google efforts to integrate other services into search, most recently last month with the addition of airline flight information derived from its acquisition last year of ITA Software. Adding in-house services like this, including shopping and maps, unfairly favours the company's own services and risks killing innovation on the Web, critics warn.
Google argues that bringing in results from specialized, or "vertical", services like this benefits users by giving them direct answers to questions. It also said last week that it would be happy to draw on content from other social services but that it was unable to access the content adequately.
Regulators at the Federal Trade Commission, which began a wider anti-trust review of Google in the middle of last year, indicated last week that they would add the Google+ case to their investigation, according to a person familiar with the situation. Regulators had yet to show their hand late last week with any requests for information, another person said, though several people involved said it appeared inevitable that the incident would be added to the case file, given the wider issues already under review.
For its part, Twitter has carefully avoided being drawn into a row with Google over anti-trust issues, instead limiting itself to accusing the company of giving up its ethical high ground by risking the quality of its search results.
One person close to Twitter's board said that the company had been caught in the middle of a fight between Google and Facebook, at whom the "Your World' feature was mainly aimed, but that the company's position would not be helped by getting into a regulatory fight. With the number of tweets growing rapidly, it already has enough content to attract users and is not reliant on search for traffic, this person said.
Another person close to the situation contrasted Twitter's stance to other companies that have been more direct in challenging Google on anti-trust grounds, including taking their cases to Washington. These companies, including travel search company Kayak and local information service Yelp, risk casting themselves as victims of Google's continued dominance, this person said.
Legal precedents also suggest that regulators might find it hard to lean on the Google+ incident if they eventually mount a case against Google for preferring its own services, said Gary Reback, a Silicon Valley lawyer who represents other Google rivals.
They would have to show that the company was illegally "tying" its social networking service to search in order to gain an unfair advantage in a new market, he added – a principle that was not upheld when a U.S. appeal court looked at Microsoft's tactic of tying its browser to the Windows operating system in order to dominate the browser market.