Email Alias is simply a forwarding email address or it can be an extra email address associated with your current email inbox. In this way, a simple inbox can have more than one email address. It can be useful in different situations.
Plus Sign Trick
Consider the email id username@domain.com. If you send an email to username+test@domain.com, it will be directed to the email address username@domain.com (Not sure about this? Try this with your email address!). I think most of you might be aware of this. You can add a + sign before the @ and add anything you need. This allows you to tag and filter messages within your inbox. This feature is supported by most of the mail providers.
But does that really sound like a good idea? Nope. Here's where I want you to introduce a service like SimpleLogin.io.
SimpleLogin
When signing up for a service using email address, websites perform a bunch of checks such as, Does the mail server actually exist? Does the email server accept email? Is the email address provided actually accepted by the email server? Only upon validating all these questions, the website accepts the email address as valid and lets the user into the site. At this point most of the people have only one email address.
Simplelogin is an open source mail aliasing solution. You can get their code here. By utilizing this, you can configure a similar solution if you wish, otherwise you can use SimpleLogin for the time being.
In my previous post, I raised the issue of data breach. In most of these situations, our email ID is leaked. That's where a service such as SimpleLogin comes in. With free plan you can get around 15 different aliases with different domain names and username. You can use these email id's for whatever purpose, such as registering for a newsletter. Here SimpleLogin acts as the intermediary. When you register with different aliases for different services, this can be used to find out who is sending us spam. In addition, you can drop these e-mail ID any time. If someone spams you, you can manually turn off this alias without affecting your other aliases or mailbox.
Similar Services
These are some of the email aliasing solutions, I recommend.
SimpleLogin and Anonaddy are open source. Their free plan has almost everything you need for a daily usage. This is a good solution to overcome spam. It can also help you improve your privacy.