Webinar Roundup: Building Your E-mail List

As for that burning "how much e-mail is too much?" question, Karp said you won't know that you're sending too much e-mail until people complain or cancel their subscriptions. But given that, if you have no complaints or unsubscribes, you might not be sending enough e-mail. He recommends sending more rather than less, as it's likely busy recipients won't open all of them anyway.