The problem was that they became a spam fest, topics were being derailed and the mods cracked down on it. Whilst the forums were smaller, new members were easily recognised when they posted in the Morrowind, and to a lesser extent, the Oblivion forums, the tradition was a good one and a little bit of fun. Now, with the number of new members joining the whole process would very quickly become chaotic.
Add in, for me at least, the fact a new account does not equate to a new member. I go sick of people saying "thanks, but this is my 2nd-5th account here and I was already given one". I just decided to let it die, though I love the idea of tradition, it's time had come, for me at least.