What are advantages of this plus-addressing? Thanks to this, we can have one email account, and we can have few addresses just by adding tags. Real power of this system can be seen using gmail accounts, when there is possibility to tell what should be done automatically with incoming email containing additional string after '+' sign. In another words, i gmail such action are accessible by filters.
I will show how to create a filter. Lets create filter that looks for tag: 'todo'. Because of that me email address: firstname.lastname@example.org. Such email for example I will give to my boss that he could send me mails to that addres, and in my gmail account they automatically will be assigne to a label called e.g.: 'work_to_do'.
To begin with we need to create 'work_to_do' label. To do this, you go to Setting and than Labels in your gmail account. There new label can be created:
Then filter must be created. To make a filter first click on 'Create a filter':
and after that you create filter in two stages. Frist, you define your tag (string after plus sign in your email address):
In the second step you define what action should be done with such email. In this case we want to assign label 'work_to_do'. To do this, you check 'Apply the label' and select label to apply and you create filter:
And that's it. From this moment on, you can recieve emails in the form of email@example.com, and they automatically are labeled 'work_to_do'.
Of course, you can consequently create others 'plus-addresses', and you can create different actions for them.