I belong to a group for which I'd like to create a Google Plus circle. I already have a flat ASCII file containing the names. There are about 40 of them, and I'd prefer not to have to type each one in laboriously. Does anybody know how to do some kind of "mass subscription" to a Google Plus circle?
This is not currently possible. I have browsed the list of Chrome extensions and userscripts and there isn't anything that accomplishes your task. Best to wait for the API to reach read state.
Also popular social networks do not handle their import this way. Mass subscription sounds like something Google would try to prevent in the same way Twitter prevents that service.