Hmm, I'm having serious doubts about the 15 minutes rule..
I meant it to prevent people from answering a question correctly, and then going away..leaving us waiting for 2 hours for the new question..
But the downside is: if you answer a question correctly, your 15 min go in when the questioneer gives you the "green light"..Meaning you sit by your computer waiting for that
So, to keep things simple, it may be better to get back to basics:
a question stays for 2 hours
a new question is posted within 2 hours ..