A lot of times people hide all traces of their real identity because they know that their online behavior would effectively make them unemployable, or they don't want to risk the tiny chance of someone actually tracking you down and stealing from you or killing you, or some shit like that. Some people are also concerned about fraud and identity theft, but you need a lot more information than just someone's name in order to successfully pull it off.
But I've always made a rule for myself that anything I say on the Internet, I would say to people face to face, including colleagues and bosses. As far as theft or someone getting mad enough at me on the Internet that they'd want to kill me, well that's just not in my zone of concern.
With that said, my real name is Timothy Zhu.
Here's my website:
http://mindoftim.com/
Here's my LinkedIn:
https://www.linkedin.com/in/timothyzhu
I keep my online identity the same as real life. No "catfish" going on with me.