If you use Gmail or Yahoo! mail, you can create filters to organize your e-mails by choice. This is also called plus-addressing. For instance, if you subscribe to a program that sends daily e-mails, you can enter your e-mail address as _+keyword@____.com when you register. For example, for one of my programs I submitted my e-mail address as dnicholls88+Apple@gmail.com. This still sends an email to moc.liamg|88sllohcind#moc.liamg|88sllohcind, however, now (under Settings) you can filter any incoming email "to dnicholls88+Apple@gmail.com." You can then add a tag with a specific color to better organize your specific e-mails. You will be receiving a great deal of emails daily, and this will improve your organization and efficiency drastically.
Here you can see an example of my Gmail. I add different colors to all of my filters to make my information easier to organize: