People send the best welcome emails, not robots
quibb.com
quibb.com
If I have a problem and contact you, then your personal and prompt response is an entirely different matter. Then it is appreciated.
Given that you are sending a welcome email, a personalized one is clearly better than a robot generated one, if you can make the time for it.
Though you and others may still enjoy personally sending emails and that's fine.
If you want to do this, your friend is Rapportive, as it can quickly give you a starting point when tailoring your email and/or help you decide who to email.
One problem I've notice with Rapportive fyi - the info is a bit off/conflicting if the person has ever changed their twitter handle (rare, but it does happen).
I wish more companies sent every (even automated) email with a working mailbox to reply to.
Just out of curiosity, have you tried sending automatic welcome messages with your email address to reply to and the same open-ended request for questions and comments?
Good point re: working email address. That situation has come up a few times - the person didn't reply to my initial welcome email, but remembered that they had received it, and replied to that email when they had a question later on.