Ramakrishnan has been chief scientist for three divisions at Yahoo over the past five years (Audience, Cloud Platforms, Search). He also was a Yahoo Fellow leading applied science and research teams in Yahoo Labs, his bio says, and he worked on Yahoo's CORE personalization project, the PNUTS geo-replicated cloud service platform and the creation of Yahoo's Web of Objects through Web-scale information extraction.
Qi Lu, who is the President of Microsoft's Online Services division, also is a former Yahoo. Lu, who joined Microsoft in 2009, was Executive Vice President of Engineering of Yahoo's Search and Advertising Technology Group.
It's not all hires on the tech fellow front at Microsoft, however.
Technical fellow Mike Toutonghi left Microsoft in November 2011 -- though his bio page wasn't updated until February 2012 to reflect his departure. Toutonghi at one point led Microsoft's Advertising Platform Architecture Team. He also worked on Windows 95 and in the Microsoft eHome division.
Update: I've heard from a couple of my contacts that Mohsen Agsen, a Microsoft technical fellow working in the Developer Division, has left the company. (His Microsoft bio page doesn't reflect his departure.) Most recently, Agsen was leading the Visual C++ engineering team. He also seems to have worked on the Courier team, from his LinkedIn profile, which also describes him as President of a Hawaiian gaming company named Mobicore. I've reached out to Microsoft for more information; no word back yet.
Update No. 2 (March 22): "We can confirm that after 17 years, Mohsen left Microsoft at the end of February this year. Mohsen made many valuable contributions to the company and we wish him well as he spends more time with his family and pursues personal goals and new projects," a Microsoft spokesperson said.