When a submitted layer is published, send an email notification to the maintainers letting them know. (There is a slight conflict in that the submitter might not be the maintainer since you don't have to register, but I figure they are probably going to be the same and the maintainers are going to want to know anyway).
http://git.yoctoproject.org/cgit/cgit.cgi/layerindex-web/commit/?id=be95164aa7ca220dcfb624a464f95077a49582c1