Did iPad kill the Courier tablet?

No. the Courier was leaked before the iPad. The Courier was NEVER going to be released, it was merely an internal project to see if it could be done (or something similar). Although I am disappointed, I believe that Microsoft will simply outsource the technology to OEMs to take advantage of like they do with Windows, Windows CE, Windows Phone, Visual Studios, etc.

Lets remember Microsoft's hardware is usually limited to markets where it doesn't make sense to have an OEM take charge, ie XBox and Zune and Mouse/Keyboards.

I was going to say what a pity it is that a courier-like device isn't going to make it to the market, and why, but instead can I just quote word-by-word 'deluded spider's comment above?
And, I think this story quite proves how important it is for a company to maintain secrecy about your products untill you're actually ready to bring them out...

We won't want to fail to enjoy missing that!

To all those companies and manufacturers that produced their version of an Apple product and either labeled it themselves or had it labeled by the so called press tech experts as either a iPod "Killer", iTunes "Killer", iPhone "Killer", and now iPad "Killer", take a close look...

To actually be a "Killer" product, you need a 'KILL'!

Rest in Peace Courier and Slate, Rest in Peace...

The word on the street is that the HP Slate that Steve Ballmer raved about is also dead.

The two-screen approach is not very practical. The promo video showed some very unusual work being done in a software that doesn't exist. Meanwhile every basic app people use today...surf the web, read an e-mail, play games, watch movies...are designed for one screen. Software designers aren't used to designing for two screens, and it would take some work to come up with apps that effectively unites two separate screens. And if they are working harder to justify having the second screen, it becomes more of a liability than an asset. Why carry around two screens if you're only going use one?

I don't see how the iPad would have killed it. As flaky as Apple's been lately, I'm sure developers would welcome an alternative device to develop for.

The iPad might be sexy, but it's not the kind of workhorse that a full-blown Mac stuffed into the space of a Macbook Air display with a tablet/multitouch combo interface would be. (Trust me, I speak from experience with a tablet hackintosh of my own...) Rather than watching Apple and Adobe hold a pissing contest, we'd be running browers with a checkbox to enable flash if so desired and eventually running photoshop on a device that allows us to touch the item we're working on, rather than trying to do everything with relative input off to the side. (Again, experience...)

The iPad will probably be considered a great toy, but once the RDF kool-aid wears off, it'll be replaced by some other device that actually lets the user decide what they can and can't have, rather that waiting for Apple's blessing for everything.

The concept of a useful digital notepad is only dead until somebody releases an iPad app that can do all of the same things. If it's $50 but does the job I'd gladly pay the toll.

The Courier is/was like the concept cars shown at motor shows, except that it only existed in someone's mind, on paper & video.

Obviously MS Vapourware, but I would have loved to have seen it go to market.
I think that there may have been a kernel of truth to it though, MS obviously believed in it, otherwise they would have pushed it harder at iPad release time. The whole point of Vapourware is to reduce adoption of Real Product long enough for the Real Product to die. Vapourware shouldn't be taken out the back and shot just after the Real Product has been bought to market; that's when it should be pushed the hardest!

I must disclose that I personally absolutely Loathe Vapourware and that sort of Predatory Marketing, but it has worked for MS for decades. I don't know why they've fallen over now.