Everyone got a chuckle yesterday when Microsoft said it had hired yet another Yahoo executive, Kevin Timmons, to lead its data center group. He joined a growing number of engineers and executives who have gone to Microsoft from Yahoo since the Redmond company failed in its bid to buy Yahoo outright, and shifted into an apparent strategy of acquiring it one person at a time.

In fact, Timmons isn't the only Yahoo veteran picking up his Microsoft blue badge this week. No, this is not a joke. Confirming a tip we received, Microsoft said this morning that it has also hired Yongdong Wang, the former Yahoo vice president of international search, into an unspecified position reporting to Harry Shum, Microsoft's corporate vice president for search product development.

But wait, there's more. Microsoft also confirmed this morning that it recently hired Knut Risvik, a former Google engineering director, as a partner architect focusing on Microsoft's search platform and infrastructure. Guess where he worked before he went to Google? Yep, he was a Yahoo chief architect, having joined the Sunnyvale, Calif., company as part of its acquisition of Overture Services.

Counting Timmons, that's a total of three more Yahoo execs now in the Microsoft fold -- on top of those we knew about before this week. As noted yesterday, Microsoft CEO Steve Ballmer said in March that the company had already hired about 10 key Yahoo technologists.

Forget the incessant questions about a possible Microsoft-Yahoo partnership, someone should ask Yahoo CEO Carol Bartz at her next public appearance what she thinks about all this poaching. If anything could prompt another public f-bomb, this might be it.

By the way, our chart yesterday on the comings and goings among Microsoft, Yahoo and Google also overlooked Neal Gafter, a former Google staff software engineer who joined Microsoft as a partner architect last September. Amazingly, it appears he has never worked at Yahoo. Here's an updated version of the chart below. Thanks to the tipster who let us know about the ones we missed.