As a consumer there are several different sorts of email address that are described as “disposable” or “temporary”.
Some of them are what we might call tagged addresses – addresses that are unique, created to be given to a specific vendor. If it’s misused by the vendor, or if it’s leaked to spammers, then the address can be disabled, either by rejecting or by silently discarding mail sent to it.
Others are created for a specific use, and will only be briefly valid, either for a single email or for a short period of time (ten minutes, an hour, something like that). They typically don’t have any connection to a users “real” email address, and are just accessed via a web page. A user might use this when they’re being required to give an email address to access some sort of service but there’s no ongoing use of that email address by the service, e.g. if a vendor is making something available for download in return for an email address, but you really aren’t interested in ongoing mail from the vendor. For cost reasons, these will typically start rejecting mail rather than discarding it when they’re disabled.
Others are addresses that just discard any mail sent to them.
Still others are addresses that are normal mailboxes, but not a mailbox that the user ever reads. At one point it wasn’t unusual for people to have a gmail address to talk to their friends, and a yahoo address to give to marketers.
Why do I care?
Every now and then someone asks for a list of all the domains that are used for “disposable” emails. There are quite a few out there, with varying levels of maintenance and accuracy, for example this one or this.
I often say something like “And don’t forget yahoo.com. If you wouldn’t use yahoo.com for whatever you’re using the list of disposable addresses for, take a moment to think about what you’re doing.”
This sometimes upsets people.
But they should still think about why they want to identify whether an email address is “disposable” or “temporary”.
We want it for reporting!
Go for it. I’m not convinced it’s a particularly useful thing to measure, but why not try it and see?
We want to ensure only real people sign up for our service!
If someone is building bots to use your service, one of the easiest parts of that is to create an email address for the bot. They’re not going to be slowed down by your requiring an email address that’s not on one of these lists.
On the other hand, if someone is going out of their way to create an email address just to give to you, they’re definitely real.
We don’t want people to just enter random junk when they download our whitepaper!
That’s a good reason to spend some effort validating the email address, but there’s probably no real need to distinguish between disposable and other email addresses for that. Send the link to download the whitepaper to the email address they give you – that way there’s no benefit to them to giving you a fake email address. (And if you track the download click you’ve got something that’s almost a confirmed opt-in on the email address.)
Make it clear to them that you’ll mail them the whitepaper link up-front (and what else you plan to use it for). If they still decide that they don’t want your follow up mails, maybe you could have included some of your sales pitch in the whitepaper download?
We’re doing this to fill our sales funnel!
If someone isn’t receptive to your sales mail then they’re a negative value to you if your sales folks spend time on them. If someone isn’t interested and they give you a disposable email address that bounces, or one that never “opens” (loads images) then your normal processes will remove that from your sales automation very quickly and they won’t waste your time.
The service they’re signing up for relies on sending them email!
Then they’re going to find out fairly quickly that they made a poor choice to use an unusable email address. They’ve had a quick look at your service, if they’re still interested they’ll be back with a longer-term email address.
It’s an ongoing service they’re signing up for, but we’d like to be able to send them mail in the future!
Maybe in-app messaging, either in addition to email or only if the mail you send bounces is worth adding?
Our value proposition is that they give us an email address, we let them download something. It’s unfair if they violate that social expectation.
If someone gives you a disposable email address in this case then they don’t think the ongoing mail you’ll be sending them is of value to them, and they don’t think the tradeoff is worth it. Maybe they’re wrong? Stress how great the content / discounts / whatever you’ll send them later is going to be. Maybe they’re right. Don’t waste your time worrying about the recipient who’s not going to be receptive, and will just unsubscribe if you force them to give you their “real” email address.
We’re trying to avoid financial fraud of various types, and we think that fraud correlates with use of disposable email addresses!
Avoiding fraud is a great thing – there are commercial services who’ll help you with that, based on more information than just an email address. They may use “is this email address disposable?” as part of their automation, but they’ll also be monitoring results on an ongoing basis, rather than just downloading a random blacklist off of github.
There’s some other reason!
Go for it. But be clear with yourself why you’re distinguishing between a “disposable” email address and an email address you can’t mechanically recognise as such.