I think he means portable as being ported to other platforms. Whereas, VB isn't able to run on other platforms. However, there is a .NET project to run .NET applications on linux, which may eventually help.

Back to the topic, I would not aim so largely, find an area that intrigues you and focus on that until you know it like the back of your hand. You will be amazed how principles crossapply to other subjects and how much will overlap as you go along.