Last I checked the challenge had 6000 plus people signed up. If I was the person who had to review and respond to all tasks submitted by folks who are taking the challenge that is 6000 plus emails which to me is daunting, and there is NO way I will be able to balance work+life+responding on time to tasks so my 2 cents is as keep this in mind when you get impatient :)
I learnt the hard way, little 'always' but always does respond it may not be immediately as we would like but little will respond as and when time permits him/her to do so.
Am on the 6th task and it took me three months to figure things out but the knowledge and skills I have gained far outweigh any time delays and response delays :)