Disposable email addresses, sometimes referred to as anti-spam addresses, are email addresses that people use for a period of time and then disappear causing emails sent to that address to either bounce or get automatically filtered to the trash. No email address lasts forever but these types of addresses can have very short life spans. They can be categorised into two types. Those that exist permanently until the recipient removes them, which we will call semi-disposable, and those that exist for a short pre-defined period of time or for a set number of messages before disappearing. A semi-disposable email address is in effect an email alias. For example I have the email address shill@ but also the alias sh@. At any time I can remove the alias sh@ and the emails will start to bounce without it affecting my main email address. Many disposable email addresses are unrelated in any way to your main email address as they use a third-party email service and forward replies to your main account until the address expires.
Disposable email address services
Most ISP’s will allow you to create semi-disposable email addresses. Yahoo! Mail call the service AddressGuard. Gmail and Hotmail allow you to set up alias addresses so the new address gets delivered as normal to your main account.
Some ISP’s including Gmail and Hotmail also allow you to append a tag to your email address to create a new address. For example, if your address is firstname.lastname@example.org, then you could also use email@example.com or firstname.lastname@example.org and they would both get delivered to your inbox. You can have any text after the “+” symbol to create an infinite number of possible email addresses.
The downside of using a tag to create a disposable address is that there is no way to remove the address should it start to get spammed. It will always be valid and if you no longer want to receive anything from the address you will need to setup filters to send it to your trash. The advantage of an alias is that they can easily be deleted and the address becomes invalid and will then bounce.
If you want to create true disposable email addresses then there are many free services available such as SpamGourmet, TrashMail or Guerrilamail. Some give you the option of setting the number of messages your temporary address will receive before consuming or bouncing messages, others allow you to set a life span for the address. Some give you the option to do both.
Why do disposable email addresses exist ?
Disposable email addresses have been around for a few years now. People are very protective about their email address and are very aware that the more they give out their email address the more likely they are to receive unwanted emails and spam. The idea is that you only give your real email address to friends,colleagues and trusted sites. For everything else you use disposable or semi-disposable email addresses. You can give a different email address to every website or company that requests an email address. If you start to receive spam you not only know who shared your details but you can also simple remove the address and the spam will get consumed by the disposable address service.
How does this affect your subscriber lists ?
Semi-disposable email addresses or aliases are a standard part of email and shouldn’t really cause a problem within your subscriber list. If you’re sending relevant content at a good frequency to these addresses then the recipients will be less likely to remove the alias. Basic list maintenance such as removing your hard bounces in a timely manner will ensure that any addresses that are no longer valid will be removed from your list and not affect your reputation.
Disposable email addresses can cause more of an issue if they exist in large numbers in your lists. They can cause damage to your IP reputation and waste resources. ISP’s use engagement as a measure for deliverability. If you send to disposable email addresses that aren’t being used then the emails will likely get consumed (deleted) by the service and your level of engagement will be lower. Some disposable address services bounce emails when they are no longer used and these should be removed in the normal way.
The best solution is to stop people subscribing to your lists with disposable addresses. When requesting an email address if you tell people exactly what you need the email address for and what you are going to use if for then you are more likely to get the “real” address you are after. As a second line of defence there are services such as www.block-disposable-email.com that allow you to check for disposable addresses when the address is submitted and reject them.
It’s all about trust. If the user trusts that their email address won’t be abused then they are more likely to give you their real email address and not use a disposable address.