As someone who is clearly affected by this let me explain my reasoning.
First, I do internet marketing and SEO for a living and fully understand and appreciate its power. I have been working in this industry since 1997 and have NEVER used my real name anywhere online EVER even though I'm online 10-12 hours a day for over a decade. You will not find my name in any profile, facebook, myspace, forum, etc. All my 100's of domains use whois protection for the same reason. I am known however on all these places as simply "darnit". Its my internet persona. Why? It's simple. I draw a strong line between the internet and real life.
As a geek I know first hand how easy it is to find all kinds of information about people with just a name and location and trying to remove information from the internet is like trying to get piss out of a swimming pool. Once its out there it's never going to go away.
Not that I have anything to hide or am some uber hacker - I am however quite aware of the power of online information and I have made a personal decision since day one in this industry to draw a strong line between the internet and my personal life. Believe me if I wanted to be high in the SERP's for my name I could very easily make it happen. I instead have chosen to do exactly the opposite.
If we are going to do business I am happy to give you my business card, cell phone number, heck you can even come over to my house for a piece of pie. If we are not then I don't see any reason to divulge any personal information. All information in my profile is accurate, I have attended a biznik event, handed out business cards and yes that is my real picture. I know that Dan has a keen interest in SEO and does a very good job of it - specifically in profiles (recall the coolest guy in Seattle) however for me its a choice, I personally don't want to SEO my name, my business fine, but not me as an individual. In fact, I take great pride in the fact that you can't find anything in the SERP's with my real name.
This might seem counter intuitive to some as many small businesses rely strongly on the individual as the "face" of the business. However for me its simply a choice I have made and to be honest it hasn't affected my business one bit. I think most internet professionals understand my reasoning.
So if it comes down to protecting my identity online as a personal choice or not participating in Biznik then I wish you all well in your future endeavors and if you want to chat you are welcome to email me at darnit@gmail.com ;)