Doncaster Meeting and Programming Puzzle

Went to Doncaster for an exam board today.

The meeting room had this very impressive chandelier, which lent a lot to the proceedings.

Spent some time chatting with Colin, the external examiner, about programming matters. We were talking about good practices, properties and get/set methods and the like, and a question occurred.

“Why do some types in C# have a Length property (for example String and Array) whereas others have a Count method (for example List)? Both of them do the same thing, so it seems to be silly to have different names for them.”

Colin and I think we know the answer. But do you?