Google (GOOG) and Twitter are at odds over the search engine giant's plan to offer more personalized results.  

The micro-blogging site, which may go public this year, argues that Google is unfairly promoting its Google+ social network at Twitter's expense through its Google Search Plus Your World feature.  A leading search engine industry observer wrote today that Twitter may have a point.

"Huge debate erupted yesterday over whether it somehow favors Google+. I can see now that it clearly does, even more than I thought," writes Danny Jackson on his blog Search Engine Land, adding that the changes "turn Google+ into an essential social network for any search marketer."

Google Search Plus combines information posted on Google+ such as photos and news with users' search results.  Many pundits are predicting that Google could wind up in hot water for antitrust issues with the FTC over Google Search Plus Your World.  Marc Rotenberg, executive director of the Electronic Privacy Information Center,  told the Los Angeles Times that "We believe this is something that the FTC needs to look at."

Investors, though, shrugged off the risks of a protracted Microsoft (MSFT)-like legal battle and pushed the shares higher.  They may have been short-sighted. The stakes are high for Twitter and Facebook.   

In a statement, Twitter said it was concerned that Google's changes would make it tougher to find breaking news on its site. Facebook, which also plans a huge IPO, has declined to comment.  

Google is not allowed to index Twitter because the micro-blog did not renew an agreement with the Mountain View, Calif. company  to offer a real-time feed of Twitter messages with its results. As PC World noted, Facebook probably won't play ball with Google either given its recent settlement with the FTC  that requires it to respect the privacy of its users and subject itself to regular audits for 20 years.

The battle over the future of social networks has begun.

--Jonathan Berr doesn't own shares of any of the listed stocks.