After six years, I've decided to retire cognizance. Some of the reasons for this are practical: my time is now very limited in terms of fixing another site with other users; there were always things I had been asked to add or change, and that meant taking time to code those modifications. The site was more than a listings site, since it had articles and a map where musicians could add and rate rehearsal spaces.
There are now other listings sites which are either backed by Kickstarter (like Jazz in London) or a subscription model (like the new JazzUK one). I'm not entirely certain that I would have raised the same sort of revenue, but that isn't why I made cognizance in the first place; I think that the scene needs a free, easy-to-access, non-partisan listings site. So for those that did use it (and those that wish to), I've moved the gig listings to the schedule. The sign-in is the same, but it's more integrated with my site in terms of the look, which is less work for me. I hope you find it useful.