I get several daily e-mails from various sources. My favorites are news-based e-mails, like Retail Wire. These are super helpful to me and the information we need to get to our readers.
The e-mails that make me groan on a daily basis are the promotional ones. I can see the desperation of the major retailers just growing exponentially as places like Kohl's, Amazon, New York & Company, Athleta (now a division of Gap) and others hit my personal inbox on a near daily basis. It's a minor annoyance, but one that may force me to opt out of those, despite the sometimes appealing savings I may get out of an e-mail blast.
So my question is how often is too often? Daily is borderline stalking when it comes to "sale" e-mails, in my opinion. No one shops that much, so there's no reason to tell me about the sales on your website or in your store on a daily basis. Is weekly acceptable? Or twice a month?