Why is a raven like a writing desk?

Throw them out of the window, and you'll know.

Both can emit a sound,though it is very flat,and for neither could one mistake the back for the front

they both have quills beside that, I don't have a clue XD

I don't think that there is an actual answer for it. It might just have been something added in to make the Mad Hatter seem...well, mad!

As Hatter said, I haven't the slightest idea! I don't think there should be an answer to that because then it would make the Hatter seem more sane and i love his weird little comments like that, especially when they don't have an answer. Its kinda cute!

A raven is like a writting desk because Edgar Allan Poe has wrote in both of them...
I mean, he has wrote on a raven (his beautifull poem "The raven") and he has wrote on a desk, an actual desk...

They are both bleak and make only one note

In the original book and in every other possible published book where this riddle comes up, there isn't an answer. There never was supposed to be. It is supposed to be the un-answerable riddle.