First, I just wanted to say this was a great promotion. I'm sure we hit some sort of acceleration record for questions (and answers) both due to the grant and the prizes.
My main concern is this promotion is still going on for another week. I think it is fair to say that we have covered most of the great questions that other users out there using the search engines would want to know. I think most people have hit their desired "rank" in the contest that they can hope to achieve, others might be very close.
What I've been noticing though is lots of new users (or existing returning users) asking a bunch of questions that are extremely similar to existing questions (resulting in lots of closed questions), extremely specific questions which probably are not viable search targets or very vague "general reference" that they could either Google or quickly try themselves. They see the promotion and they struggle with getting in some questions so late in the game.
I wish I had some data to back this up, such as view count per question per date (I'm sure someone could write this for some interesting metrics). Unfortunately the data explorer has not updated for our contest. I imagine the trend would be a sharp decrease in view count for newer questions.
I can see some positives and negatives to keeping this promotion going on so long. On the positive side this means were consistently bringing in new users to the site who try to compete in the promotion, and maybe some of them will stay. However, on the down side of things there is a lot more "noise" being generated by questions as of late with duplicates, too specific or general reference style questions that I personally don't find interesting.
My question is, is this promotion going on too long, lowing the signal to noise ratio of questions in an unfavourable manor? Or do the benefits of new users outweigh the negatives described above?
(edit) I am mostly interested in opinions for future contests as I'm sure the end date of this one should be set in stone.