In my first customer engagement position, I chose to have my identity with the company unrelated to my public blogging identity.
I didn't try to hide it, per se. I simply didn't advertise it and I didn't use the Hebrew name by which I'm generally known. In my public blogging identity I use the name Yehuda. My name at the company was simply my English first name. I never mentioned on my public blog what company I was working for on the side.
Why?
One, I didn't want what I wrote on the company blog to reflect on my public blogging identity. This one is a little strange, I admit. But the company had absolutely nothing to do with my usual blogging subjects. And I really didn't like the direction and content I was asked to produce; I had to write only about the company itself or the company's site, every day.
I hope to never find myself in this position again.
Two, should I ever stop working for the company, as I in fact did, I didn't want searches for my name to be confused.
Three, the company didn't want to be responsible for anything I wrote about on my personal blog.
As to this, the decision as to whether you link identities may be up to you, or the company, or a joint agreement.
As Gavin pointed out in the comments on the last post, you may simply be writing a blog which is supposed to be popular but not necessarily directly related to the company or product. In which case, hiding your identity doesn't seem to make much sense. It's just another blog you write.
On the other hand, if you're representing the company and blogging about company things, it might make sense to hide your identity. Programmers and managers may go through more than one company in their work life, but they usually don't work publicly in two locations at once, I think. Marketers might, but their name isn't usually public anyway, only the name of the ad agency they work for.
My new company is in the game industry, which overlaps with my public blogging identity. When the company publicizes, I will probably declare my identity by my public name (Yehuda). I will have to disclose my new company relationship on my own blog so that people know this if I promote the company's service or product, or speak about other companies or products in the same field.
The benefit to blogging under my public name is that I can build on the relationships I have established. Of course, these relationships were established before I joined this company, so any such building will have to be delicately done indeed. I have to really believe in the new company and their product. And I don't want my friendly relationships to turn sour. It's a delicate line to walk.
One more issue about two blogging identities is the issue of leaving comments on blogs. This affects you even if you have a single identity, but run more than one blog.
When I was working for my first company, when I left a comment in the capacity of my work I left it in my work's identity and with my name linked to my work blog. Since there was no overlap between the places I would normally leave comments, and the places I left comments in the capacity of working for the company, there wasn't any conflict.
In my new job I will have to decide when I am leaving a comment if it's on behalf of myself or my new company. Though both my public blog and the company are in the game industry, they encompass slightly different niches within the industry, so I may get off without too much difficulty.
If you have two blogs, you have to decide the same thing. If you sometimes leave back links to one blog and sometimes to another, this results in splitting the effectiveness of your commenting by splitting the resulting back traffic to more than one location.
Yehuda