Stack exchange websites such as this are clearly intended for cut and dried math questions and answers, and loosely framed or open-ended questions are given short shrift and soon closed down by ever vigilant moderators, and I suspect even this meta-question will be frowned upon!
This is fine in its way, but are there websites where thoughts on or suggestions for possible approaches to open problems can be discussed?
Usenet groups such as sci.math used to be just the ticket for this purpose, but alas in recent years these, certainly the unmoderated groups, have been overrun by spam and presumably forsaken by knowledgeable contributors, and their entropy quotient is now close to unity!