I've found a clue as to how this list was put together.
I noticed a few British series on the list, which stuck out since these things generally keep to American and Japanese stuff. Then I realised that they're pretty much the same selection of UK cartoons that turned up on Channel 4's top 100:
Channel 4's list has Charley Says, Jamie and the Magic Torch, Roobarb, Noggin the Nog, Willo the Wisp, Captain Pugwash, 2DTV, Bod, Ivor the Engine, Danger Mouse and Wallace and Gromit. This list has all of those plus Bob the Builder, Duckula, Rupert and something called Thomas the Train (which I'm guessing is Thomas the Tank Engine), and at least three of those four aired in America.
Makes me wonder if the whole thing's compiled from several different lists.