Raghavan, a 14-year veteran of IBM who led the Computer Science Principles department at Big Blue's Almaden Research Center, will report to Usama Fayyad, Yahoo's chief data officer and senior vice president.
"The appointment of Prabhakar into this key role at Yahoo! indicates the significant degree of importance Yahoo is placing on research," Terry Semel, chief executive of the Sunnyvale, Calif., company, said in a statement.
Raghavan left IBM to work as chief technology officer of Verity Inc., which develops enterprise search software. He is currently editor-in-chief of the Journal of Association for Computing Machinery, and a consulting professor of computer science at Stanford University.