If you send email marketing campaigns to your customers on a regular basis, listen up. Recent big changes by some major Internet service providers, or ISPs--specifically, AOL and Yahoo--might be blocking your emails from getting through to your recipients.
Basically, AOL and Yahoo are checking whether emails with addresses hailing from their specific domains (for example, email@example.com or firstname.lastname@example.org) are really being sent from their mail servers. An email that says it's from email@example.com or firstname.lastname@example.org but is not really being mailed from AOL's or Yahoo's servers will get bounced or sent to the spam folder. AOL and Yahoo are doing this to combat the rise of phishing and spam in email sent to and from their users.
Other ISPs (Hotmail, Gmail, etc.) might follow suit, so it's important to understand what's happening and how to make sure your legitimate emails are getting through.
Here's the issue: If you use an email service provider to send email marketing campaigns (like MailChimp, Constant Contact, or my company, VerticalResponse), your emails are actually sent through a third-party server.
If you have an @yahoo.com or @aol.com address in your "from" email address line and use an e-mail service provider to deliver your emails, these recent changes might cause your emails to get bounced or sent to spam, even though they are not fraudulent.
The easiest way to combat this issue is not to use an @yahoo.com or @aol.com address in the "from" email address line for your e-mail marketing campaigns. I strongly recommend you use a "from" address that's a private domain, like email@example.com. This way, if Hotmail, Gmail, and others decide to also implement these changes, you won't be affected.
Got questions? Post them in the comments below and I'll try my best to answer.