Reuters, April 25, by Anupreeta Das
http://news.yahoo.com/s/nm/20080425/tc_nm/google_yahoo_dc_1
“The general rule would be that if the arrangement substantially limits competition in some aspect of their business, that would be problematic,” said Aaron Edlin…. “Collaboration that comes short of merger is much more apt to pass muster before antitrust authorities,” he said.