It depends on your potential clients, of course. What I was cautioning against in my article is spending a lot of time and money on the trappings of a business -- LLC or corporation paperwork, accounting, web site, business cards, office, separate phone number, etc. You don't need any of those things to get started freelancing, and it's easy to get caught up in that non-productive stuff because there's an industry profiting from selling the form and trappings of entrepreneurship, when what you really need is the substance.

Most networking is done with smartphones and social media these days. Business cards can be handy, but far more often I exchange email addresses and phone numbers (or Twitter handles or whatever) with someone I want to follow up with, or who may want to hire me. It's important to be findable online. Potential customers you meet or who hear about you from someone else will more likely be looking for you by name. A blog with prominent and current contact info works, as does a public LinkedIn or GitHub profile.

I'm always a little skeptical of so-called freelancers who have the trappings of an important consulting firm but give the impression that that's all they have.