I have my inotify watch limit set to 1024 (I think the default is 128?). Despite that, yeoman, Guard and Dropbox constantly fail, and tell me to up my inotify limit. Before do
I think
sudo ls -l /proc/*/fd/* | grep notify
might be of use. You'll get a list of the pids that have a inotify fd registered.
I don't know how to get more info than this! HTH