Yup, it's official, WPF/E is now Silverlight. Once upon a time, I used to get annoyed at the marketing department for these changes. "Why can't these guys just pick a name and stick with it? And why is it such a big secret until we officially release it? It's just a name, how important could it be?" But, over time, I've learned to appreciate why marketing does this (even if it does cause me occasional grief).
A lot of marketing is about finding a way to explain the essence of the product to people really, really fast. There's a lot of products in the world, far too many for any one person to pay attention to all of them. You don't even have enough time to spend 30 seconds on each of them -- you want to know whether that product is relevant, in three words or less. And that's where the marketing department shines, finding names where your gut reaction is the correct one. Quick, what operating system does Windows Presentation Foundation run on?
Another thing I've come to accept is that like anything else, it takes time and multiple iterations to get the marketing right. What we now call .Net 3.0 was initially WinFX, until we learned how much it was confusing people who were using .Net. And while you can do a lot of planning up front, there's no substitution for testing a name in the real world.
The final mystery to me was why the secrecy. Are we really worried about someone taking the name Windows Presentation Foundation before we get it? Sure, we want to get the domain name & trademark before someone else squats on them. But mostly it's about creating the most "buzz", by which I mean free advertising. All that news coverage of a product announcement, that's worth millions of dollars of advertising in the amount of customer awareness it generates.
So while I'm not thrilled about updating the name of my blog yet again, I sleep better knowing that we have smart people making sure we get the most out of our product names.