The specific feature that I'm looking for is to be able to send out a message in response to someone subscribing to a websites newsletter.
I've been reading over the forum threads for a bit and it seems like others have hit on the same idea and the response is that it would be a significant effort to add this functionality (and reading the code, it's understandable, e-newsletter is just records in a separate table which is probably far more secure than creating users that triggers auto message).
Reading through the code, I don't see it as a significant effort to implement at first, an auto response and then auto message's functionality in the e-newsletter plugin on the subscribe action.
If I were to implement this, is WPMU willing to accept it back and add it to the module (assuming the code to up to their standard)? I don't want to be left continuously adding the patch onto updates.