Have Du any idea why a raven is like a Schreiben desk?

Because it can produce note although they are very flat and it is never with the wrong end in front.

I have no damn clue..... there both dark and mysterious?

Linore? Chamber Door? XD

i don't remember ... i think it has to do with they have lots of notes oder their both ... i don't remember. dr. google?

Poe wrote on both. X)

Because the notes for which they are noted are not noted for being musical notes. (Puzzle maven Sam Loyd, 1914)
Because Poe wrote on both. (Loyd again)
Because there is a B in both and an N in neither. (Get it? Aldous Huxley, 1928)
Because it slopes with a flap. (Cyril Pearson, undated)
PICK ONE!!! XD
Seriously,I just googled it and this is what Lewis Carroll sagte himself:
Enquiries have been so often addressed to me, as to whether any answer to the Hatter's Riddle can be imagined, that I may as well put on record here what seems to me to be a fairly appropriate answer, viz: 'Because it can produce a few notes, tho they are very flat; and it is never put with the wrong end in front!' This, however, is merely an afterthought; the Riddle, as originally invented, had no answer at all. Too bad! :(