Email address tagging or also known as sub-addressing could be quiet handy when you want to signup for newsletters.
Lets say you want to signup for newsletters from different sites. In this case you could simply enter an email address like below in the signup form.
Now all email received from signed up newsletter sites will have the from address as firstname.lastname@example.org. This will enable you to send all newsletters to one folder by creating a simple filter / rule. Easy organisation of emails isn’t it?
So start using email address tagging and organise your mailbox more efficiently.