One of the truths of email marketing is that, for a variety of reasons, email domains can very greatly in their reliability. Different domains have unique demographics and functionality that can make the addresses more or less valuable. Free email addresses are typically of the lowest quality, likely due to the fact that they are easy to obtain and can be thrown away at a moments notice with no consequence to the user. Some of the most common free email domains are hotmail.com, yahoo.com, and gmail.com. While gmail has been consistently better than the others, its addresses are still less reliable.
In our experience, yahoo.com addresses are among the worst of free email addresses. We're not exactly sure why this is, but it seems to come down to a combination of a user base who doesn't seem to hold on to their email address for very long and the poor functionality of the over zealousness of Yahoo's mail server filters. Often Yahoo will be slow to deliver mail or will categorize an email as spam without justifiable reason. Email lists with a large number of Yahoo addresses have more trouble and see less results than other domains.
Because of our many years of experience and having dealt with them very often, we have had success with being delivered to Yahoo addresses. There is nothing we can do about the quality of the addresses, but we do everything in our power to get them delivered. If you have a list with a large amount of Yahoo addresses, you may want to reconsider your collection methods.
Much of this applies to all free email address. Many people use free email addresses so it's hard to know when you have an issue. It's important to consider where you are collecting your email address and from what type of people. If you need further advice or would like to discuss your own list, we'd be happy to help! Give us a call anytime at 800-479-6233!