I've been curious about this for a while. Where / how did Skritter get its database of stroke orders, decompositions etc. Are there lists available? Or did someone have to enter the whole lot manually?

Well the stroke order data was all lovingly handcrafted by ourselves, mostly Nick and George, especially George. Much of the other data has been seeded from various sources, listed in our legal page:

http://www.skritter.com/legal

The components in particular, I forget what source Nick used for that. Will have to check with him when he gets back from the holidays!