Good guess, Stilly. All that is required for a thread like this to eventually spawn itself is for a few loquacious people with too much time on their hands to develop the habit of dropping in every day to see what is happening and contributing their various bits of idle verbiage to the ever-growing list of posts.

At first they find it merely amusing or diverting.

Presently it becomes a regular habit which they can barely do without.

Then it becomes a sort of unholy addiction...a retreat from the hurly-burly of real life into an evermore exclusive gathering of similarly-minded souls who derive comfort from the little club they have unintentionally formed.

Soon they feel a real sense of ownership over the proceedings in their thread, and they regard new or occasional visitors with suspicion, indulgent tolerance, or lofty disdain...depending on what sort of mood they're in that day.

Then it becomes a holy crusade to maintain the thread on a daily basis, enlarge it, expound upon its unique and special value, and defend its continued existence against any possible threats.

In short: intellectual incest!

I put it to you that the Walkabouts thread is beginning to show strong signs of becoming just such a thread, while the MOABS is the ultimate example of the type. ;-D