One way is checking the domain registration. For example, you can see that I registered CLINICALCASES.ORG with my work address.
Quick Online Tips blog writes that you can type the URL of any (hosted) blog in Whois.sc and see the personal details of the person who registered that domain name.
Of course, this excludes people who blog on free services like Blogger.com or Wordpress.com. If you want to protect your confidential information when registering a website, you can opt in for a private domain registration.
I wrote this post 10 months ago, in March 2006, and never got around to publish it. MSSPNexus Blog just pointed my attention to Dr. Anonymous who was recently featured on Fox News and soon after that has discovered that he's not so anonymous after all:
1. FoxNews.com features Doctor Anonymous
2. Is Dr. A a quack?
3. Dr. A Revealed
4. The Myth of Anonymous Blogging
He has posted 2 videos explaining why he is "blog-aholic" and why he wants to remain anonymous. Well, if you want to stay anonymous, posting your video is probably not the best move, but who am I to judge others...
Why Private Domain Name Registration is Essential. Quick Online Tips.
Simply Fired - How NOT to Blog About Your Job. Especially If You Are a Doctor
Great moments in Amazon packaging: Updated and Bumped. GruntDoc, 03/2008: "...this is a semi-anonymous blog, and within a day of posting Amazon figured out who I was without any trouble whatever. Don’t think you’re anonymous on the internet."
Doctors in Social Media Shouldn't Be Anonymous. 33 Charts, 2009.
Anonymous Blogging 101: a Quick and Dirty Primer. ProBlogger, 2010.