Should prospective employees be judged by the size of their networks?
That study suggests that the more connections within a company you have, the better you'll do in that company.
It doesn't talk about outside the company connections.
You're right:
http://www.businessweek.com/technology/content/apr2009/tc2009047_031301.htm
I think it's safe to assume people who are good at networking in general, ceteris paribus, will network more inside the company as well.
That's good news, since networking is something anyone can get good at with practice.