NEW YORK • Columbia law professor Tim Wu is known for coining the term "net neutrality", widely used to describe Internet service in which all data is treated equally.
Now Google Search is in the firing line following a study by top academics from Columbia and Harvard led by Professor Wu.
Paid for by one of Google's rivals, the study released on Monday suggested that Google sometimes alters results to play up its own content despite people's preferences.
In the study, the researchers presented 2,690 Web users with two versions of Google.
One version showed search results for local businesses as users usually see them, with links to the businesses along with ratings as posted to a Google site.
SPIN VS SCIENCE
Overall, it comes across more to me as a public relations exercise rather than precise science.
MR DANNY SULLIVAN, a search engine analyst and the founder of Search Engine Land, about the study commissioned by Yelp
The other version showed links to businesses along with ratings from rival sites like Yelp, the online review website, which paid for the study.
The people studied were 45 per cent more likely to click on links if Yelp and other competitors were included - a sign, researchers say, that users prefer more diverse search results.
The study could renew calls for regulators in the United States to reopen an inquiry into Google for unfairly promoting its own services.
It may also provide more ammunition to officials in Europe who have accused the US Internet giant of anti- trust violations.
"The idea that you can build a better version of Google's search engine pretty easily if you don't exclude competitors, to me, was a pretty startling finding," said Prof Wu.
Yelp has become one of Google's most vocal competitors. On Monday, it promoted the study with a website and YouTube video to explain the findings. But Yelp's biggest promotional asset may be Prof Wu himself.
He has defended Google's competitive practices in the past, but said he was swayed after speaking to a Yelp executive last year and looking at internal data Yelp had collected on Google.
Google has questioned the results, saying: "This isn't new."
The company said in a statement: "Yelp's been making these arguments to regulators, and demanding higher placement in search results, for the past five years.
"This latest study is based on a flawed methodology that focuses on results for just a handful of cherry-picked queries. At Google we focus on trying to provide the best results for our users."
Some outside experts, too, have questioned the findings.
Lots of clicks can be sign of irritation, they said, rather than satisfaction, like if users keep navigating from Google to Yelp and back again.
It is also difficult to discern whether users were more engaged with Google during the test because the results were more relevant, or merely because the page had a different look.
"Overall, it comes across more to me as a public relations exercise rather than precise science," said Mr Danny Sullivan, a search engine analyst and the founder of Search Engine Land, a site about the search industry. "However, I do think Google could easily include links to other review sites which would benefit both its users and competitors."
In April, European Union officials accused Google of unfairly manipulating search results, the first time it has faced such charges.
NEW YORK TIMES