Personally I think Yahoosoft rolls of the tongue better however I don’t think they will get top billing if Steve Ballmer’s marriage proposal gets the formal yes.
I am both a Yahoo! and Microsoft Alumni which give me a rather cool perspective on this. The cultures are similar in that they are both founded by engineers however Yahoo! is clearly inferior in terms of being able to cope with growth and maturity into a major corporation. While I am sure there will be some riffing, MS is clever enough to recognise talent so I don’t think any of my old friends need to worry too much about aquisition pain. For those people that thought Yahoo! was just one big gravy-train: you know who you are and I would be worried.