Grargar: You might not like comparisons, but at its simplest level, you give money lo someone with the promises that you will get a product. The rest are semantics. It's worse because your money are taken long before the product is delivered.
Oh that is... First of all, why am I having this discussion: Spreading of the 'KS is a preorder' belief is actively hurting kickstarter, so please, stop it. Now as to why it's so wrong (and no, it's not semantics - there are substancial differences between the two.)
Preorder - you give money in advance for an already finished product. Preorders are pointless, because the product is finished whether or not you decide to give the project your money, and the only one who wins here is publisher, who gets sales even for a completely disasterous game.
Kickstarter - it's a form of patronage, dotation. Someone shows up with an idea, and if you choose to do so, you might back that idea up with your money. You are doing so with the inherent risk of losing your money completely or getting a different product that you have expected it to be. Now the last bit is the important one, because it means you should only back KS projects with money you are not sorry about losing to it completely - however, without your money, the project wouldn't even have a chance of being born in the first place.
If, in your eyes, substancial differences in approach, results and aim are 'semantics', then I am preordering Dwarf Fortress by donating to the project. And the reason why spreading the 'KS is preorder' drivel is dangerous is because people will start believing it, they will approach KS with their money, and then they will be disappointed that they didn't get the product they have bought (even tho they have never bought it in the first place.) This is hurting services similar to kickstarter by making them appear dishonest, even tho they were honest about this from the getgo.