The longstanding and persistent accusation that Google unfairly uses its search engine to promote its other online services is once again in the spotlight, triggered by new social search functionality the company is rolling out this week that more tightly links its search engine with its Google+ social networking site.

The complaints have come from different quarters, including competitors and industry experts, and have focused on various arguments, but at bottom all charge Google with using its dominant search engine to deliberately boost Google+’s popularity, by giving Google+ pages and profiles an artificially prominent position in result pages.

Unfair competition

One of the strongest arguments made so far comes from search engine expert Danny Sullivan, who described on his technology news site Search Engine Land how Google is now suggesting Google+ business pages that companies and public figures have set up on the site in a way that makes the Google+ pages much more prominent than similar pages these public figures and organizations have set up on competing social media sites.

Sullivan shows a variety of examples in which Google, via new query auto-complete suggestions for Google+ profiles and via the new Google+ People and Pages sidebar suggestions column, favors Google+ business pages over alternative ones that have more “fans” on Facebook and Twitter.

Sullivan ran his queries without being logged into his Google Account, and even using the Chrome browser’s “incognito” mode, to make sure that the Google search engine treated his queries as coming from a fairly generic user, and not tailored to him specifically.

“Is there anyone out there who still wants to say that being on Google+ doesn’t matter? Anyone? Because when being on Google+ means that you potentially can have your Google+ page leap to the top in those sidebar results, Google+ matters. It matters more than ever before,” he wrote, adding that Google is clearly “taking its weight in search and leveraging it to boost Google+ in a big way”.

Key product

Google, after many missteps in the social networking market, launched Google+ in mid-2011, and has made it clear, from CEO Larry Page on down, that Google+ will be a key, unifying product for the company, providing social sharing features and an identity layer across most Google online services.

However, there has been skepticism regarding the adoption and engagement level for Google+, especially when compared with social networking leader Facebook, which has more than 850 million active members who spend a lot of time on the site.

Google+ is also a rival to Twitter because Google+ can be used in similar ways as the microblogging phenomenon.

In fact, among the first to cry foul this week was Twitter. Its General Counsel Alex Macgillivray, who previously worked at Google, posted on his Twitter account that Tuesday was “a bad day for the Internet” after Google announced the new search functionality.

“Having been there, I can imagine the dissension @Google to search being warped this way,” he wrote. Twitter later followed Macgillivray’s post with a more formal statement, in which it reiterated and expanded on his complaint.

Meanwhile, Google answered back with a post on its main Google+ page, saying it was “a bit surprised by Twitter’s comments” because Twitter “chose not to renew their agreement with us last summer,” a reference to the now lapsed two year deal which gave Google special access to Twitter’s “firehose” of real-time tweets.

However, as Sullivan and others have pointed out, Google has continued indexing Twitter posts and has a massive collection of them in its index, including links to the official accounts of public figures, celebrities and organizations.

Silence from Facebook

Throughout the two day flap, Facebook officials have remained mum. Facebook has its own special search arrangement with its partner Microsoft, which gives the Bing search engine access to certain data that is out of Google’s reach. While Facebook keeps most personal profile content off limits to search engines, its business profiles are public, as well as some other content, and thus available to Google.

In fact, for a while Facebook has let individuals tag status updates as “public” and made those available to search engines, a good example of this is the site YourOpenBook, devoted exclusively to this type of public status update.

In its announcement on Tuesday of the new social search features, described by the company as “Search, Plus Your World,” Google focused on new things its search users will be able to do when signed into their Google accounts: find Google+ posts and Picasa Web photos they and their contacts on those social media sites have shared not only publicly on the web but also privately with each other.

This new functionality builds on the existing Google social search features, which let users logged into their Google Accounts see links in search results that their specific social media contacts tagged with the Google +1 button or shared publicly using a social media service.

Google didn’t respond to a request for comment about the controversy surrounding the new social search functionality.