This is an excellent question!!
I love the link too EdShaz - a great article
I think there are two aspects here:
The 'You' persona - where you use your real name for things like Twitter, Friendfeed etc.
And then your Niche Persona's (in some instances they may be the same ie: if you are in the IM niche, or say make Fountain Pens etc).
In both instance's I agree totally with Dr Mani's article - it is YOU that people buy into.
Both your expertise and your character/personality.
My opinion is that it is good to share some of 'You' - the authentic you, with your audience (you can do this also in you niche when you have a pen name - you may have the same interests, same birthday - you just have a different name).
And I believe you can share the authentic YOU, AND maintain privacy.
I don't believe the two are mutually exclusive.
I guess you just become conscious as to what you want to share as the authentic you to the IM audience.
Ed Dale is an excellent example of this - we know he took Hannah and Molly to Mama Mia the other night...we know his wife's name is Julie. We know Hannah had a Tae Kwon Do competition recently.
AND we do not know the intimate details of their day to day lives - as that is their private business.
So I would offer that you can be real and be 'you', and just be conscious about how much and what you choose to share.
And that you DO have control of that.
Best to you
Caro