When I got the email that they were shutting down the API at the end of April, the first thing I rushed to check up on was the status of Leaflet.js (which I think had been sponsored by Cloudmade?). Fortunately, it seems it's now sponsored by Mapbox: http://leafletjs.com/2013/11/18/leaflet-0-7-released-plans-f...
Probably me reading too much in to the email but I got the feeling that Cloudmade wasn't going to be around for much longer and worried what that would mean for leaflet development.