Levels of abstraction

The other day I was .. "surfing the web" (which these days means looking at an endless twitter feed) when I stumbled across an interesting (and very long) post about a programmer's career and how to not screw it up, basically. One point Patrick made was about communication. Let me copy the paragraph and discuss it later:

A Github portfolio

In many professions, having a portfolio is a really good way of letting your work speak for yourself. A portfolio of your past work can help a potential employer decide whether they are going to hire you, and colleagues see what you're made of, and it often much more useful than a CV. Programmers can have portfolios too, in the form of public repositories, which is why I'm starting my own using Github.