Advise Expectation of a Reply

If someone expects a reply to an e-mail, should it be stated in the e-mail? And, what about a general e-mail that has been addressed to a large group for informational purposes?

As far as stating you expect a response, not necessarily. When someone takes the time to e-mail another, common courtesy dictates that you respond on a timely basis. To not respond because the sender didn't ask you to, can be perceived as you ignoring the sender and that's just isn't nice.

Now this certainly doesn't apply to spam, forwarded chain letter e-mails or those e-mail that are from folks you don't know.

Responding promptly, even if to just send a "Thank You" helps build relationships and avoid misunderstandings.

As far as informative mass e-mails, I would assume a reply is not expected if it is announcement type e-mail. The exception would be if you have specific issue with something in the e-mail that you feel the sender needs to be aware of. In that case, I would reply directly to the sender--and NOT Reply to All.