Not quite as concise as I'd hoped for (I guess that's my fault for not including "concise" in my request), but thanks nonetheless for providing that definition. Now, I'll state first that it's not my intent to start quibbling about definitions, but please humor me while I point out a few places where my own definition differs; I'll get to the primary point i wanted to make shortly.
First, I wouldn't consider it necessary that the code execute during the routine operation of a product. For example, there have been a few flavors of Securom that only use online activation upon installation (or upon a hardware change), yet I'd still consider that DRM. Similarly with the already mentioned example of Windows activation. I'm also not too keen on including intent in the definition, as that tends to make things far too nebulous; I generally prefer to simply look at what something does as opposed to what the purported intention of it is. Additionally, I think a key part of what defines DRM is that it is extraneous to the function of the product. For example, having to connect to a central server when playing online multiplayer on that server would not be DRM, while having to connect to that server for single-player or LAN play would be DRM, as in the two latter cases connecting to the server is extraneous to the function of the product.
But as I said earlier, it's not my intent to quibble over definitions. The point I wanted to make and illustrate was that you have a definition for what DRM is, I have a slightly different definition for what it is, as does korell, bansama, Lucibel, and probably most everyone else on this forum. There's plenty of overlap in those definitions, but there's also some differences, and it's from those differences that the "it's DRM", "No, it's not!" bickering comes from. This is a problem that will always be around when you have a term that does not have a clear, concise, well-established definition. For this reason, statements such as "X is DRM" and "X is not DRM" are rather silly, as such statements will carry different meanings for everyone, and thus don't really convey anything meaningful. Instead of just applying the broad label of "DRM" to something (or trying to refute the use of that label) it's far more productive to simply state what something actually does then let people individually decide which of their own labels applies.