There is a well-known design firm named 37 Signals (actually, they're more of a software company these days, but they started off as a web design firm.) They write a popular blog and they published a few books. They are smart folks and a lot of their ideas are innovative. One thing that I've seen them speak out against is the idea of professionalism, portraying it as a negative quality. I couldn't disagree with them more.
"Getting Real"is the title of their first book and I think it well encapsulates their feeling about the idea of "professionalism". We live in a world that puts a heavy emphasis on symbols rather than the reality of situations: where you went to school, how you dress, what certifications you possess, and etc. Most geeks see through the symbols and champion those who demonstrate the lack of reality in those symbols. A great example of this is when Mark Zuckerberg, in the Social Network, goes to a meeting with a bunch of high-powered venture capitalists in his bathrobe. He possesses real power and demonstrates it by not conforming to business dress mores. We love that scene, because we know that in reality the symbols don’t matter. All that matters is what you can do.
I understand and agree with the importance of "real". In my years in the Marines, I knew many individuals who were masters at exhibiting the symbols of competence without actually being competent. However, professionalism as a Marine was still important and it's just as important in business. The symbols of professionalism may be little more than indicators, but the code of conduct they represent is critical. It doesn't matter whether a MIT grad or a community college alumnus built an application, but it does matter that it's well designed and delivered on time and within budget. Professionalism is still about what you do, it's just putting constraints on how you do it. Because how you do it does matter.
The code of conduct for a professional concerns working well. That means keeping your word, being reliable, and getting things done. The cost of working with someone who isn't a professional, regardless of whether they're in a business suit or a bathrobe, is high. Dealing with individuals who lack professionalism introduces friction and uncertainty into your project. This incurs a substantial cost in time and resources. It also incurs emotional costs to the people who have to deal with these individuals. Every business should work with competent developers, but as important and often overlooked is the need to work with professionals. Whether your business is looking to hire an employee or outsource a project you should be gauging the candidate's professionalism as much as their ability.