Another good reason for establishing a corporate email address as distinct from a GMail, AOL, Rogers, Sympatico Or Yahoo account):
Take a trip to http://www.varicent.com and try to download one or more of their white papers.
The submission form detects obvious web-mail domains such as gmail.com and asks instead for a corporate email address.
Fair enough. They are delivering to you the results of their hard work; you pay with a real email address.
Traps for young players: The form is reset with the "Yes, I want to receive periodic email updates from Varicent" box checked ON, so if you have a corporate email address, by default, if you are not careful, you are going to receive emails you may not want.
Of course, if your only emails are mailto:email@example.com, you aren't going to be taken seriously by this firm, and that applies not only to your request for white papers, but also to any email communication you may engage in regarding your services.