Cookie licking is the act of claiming something as something only you can do, but without actually doing it. (Note: This is considered a bad thing.)
I have not seen this particular phrase in action, but I'm under the impression it comes from the Microsoft Research part of campus.
The metaphor employed here is a plate of cookies. You've pigged out on cookies and you're full, but you take a cookie, lick it, and then put it back on the plate. Since nobody wants to eat a cookie that somebody else has licked, this effectively allows you to claim the cookie without actually having to eat it. (You never even had to put it on your plate.)
Suppose there is a list of items to be done, say, tasks or projects or topics for investigation. Somebody signals interest in a particular project, thereby making it unavailable for others to work on. If the person never actually starts working on the project, then that person is accused of engaging in cookie licking.
Cookie licking takes place at higher levels, too. For example, one team might come up with an idea for a feature, but they will be told by another team, "That's something we've been thinking about for a while," as a way for the second team to take control of the feature away from the first team. In extreme cases, that other team may not actually have been thinking about the feature at all, but by merely saying that they have, they have asserted their claim to it.
Explaining it again: In the comments, it looks like someone else doesn't quite understand what cookie licking is, since he/she brings up a number of examples which aren't cookie licking. Since other people might be similarly mistaken, let me try again.
Cookie licking is a tactic to prevent somebody from doing something by saying that only you can do it. It's a way of taking things away from others.
"Announcing an OS without actually delivering quickly" is not cookie licking. Announcing the OS doesn't prevent other companies from developing their own. Announcing a product and delivering it late is embarrassing, but it's not cookie licking.
Similarly, announcing a successor product, which stifles interest in the current product is not cookie licking. The current product is already out there; nobody took it away. The marketing team may have made a serious error in judgement, but no cookie licking took place.
In both cases, the examples fail to capture the concept of preventing people from doing something by saying that only you can do it. It is a political tactic internal to an organization, not something done in public.