I have 2 email addresses. I give one of them to unimportant people who are likely to send me a bunch of forwards and other crap that I don't care about. I give my other email address to important people. I check the email for important people hourly, and I check the email for unimportant people like once a week, and I just skim through it then.
Maybe somebody gave you their email address for unimportant people.
I don't mind if unimportant e-mails don't get a response. I have sent 4,738 unimportant e-mails over the last few years and many of them don't get a response (Meek

). I get frustrated, though, when I send an important e-mail to an important (or somewhat important) person, one that requires an immediate (or somewhat immediate) response, and don't get a reply.