The FTC broke with its usual practice of requiring a consent decree to settle an investigation. Instead it allowed Google to write a letter pledging to implement the agreed-upon changes in the search portion of the probe.
That prompted some sharp questions about whether Google would live up to its pact.
"I have no reason to think that Google won't honor their commitment; I think they will," said Leibowitz, noting financial penalties if Google failed to do so.
One Google competitor seemed to think the FTC agreement with Google would be a small boon to competitors.
"The concessions that the FTC extracted on review scraping, patents, and data are real, but not game changers by any means," said Oren Etzioni, co-founder of Decide.com, a product website that advises shoppers when prices may change or new versions of gadgets may come out.
Some of Google's critics, anticipating a weak conclusion to the FTC's investigation, said in December that they may be ready to take their grievances to the Justice Department.
The European Union, based in Brussels, is conducting a parallel probe of Google. It announced on December 18 that it was giving the company a month to come up with proposals to resolve its probe.
The European Commission has been examining informal settlement proposals from Google since July but has not sought feedback from the complainants, suggesting it is not convinced by what Google has put on the table so far.
Google is also being looked at by a group of state attorneys general, led by Texas.
In August, Google was forced to pay $22.5 million to settle charges it bypassed the privacy settings of customers using Apple Inc's Safari browser. The practice was in violation of a 2011 consent decree with the FTC over a botched rollout of the now defunct social network Buzz.
