Sorry, we are now stretching the term "portfolio". Your link is what I would call an item in your resume, with a quick summary about which you would be ready to talk during the interview.

I think when Jeff Atwood says "portfolio" he means not just things you'd put on your resume, but source code and publicly available articles you've written, and for some reason a twitter account.

But not just "I developed that closed source project, over there." That's what everyone has on their resume.

-- Ninja Edit---

Actually I just looked at Jeff's other article, and apparently what he calls a "portfolio", is what I call a well written resume.