When someone has piqued your interest, be sure to search for them on Google. Whatever their username is, put that name within quotes in your Google search bar. Like this:
If you just type in their username, Google will show you lots of results that are irrelevant. When you put the username within quotes, Google results will show any webpage that has that exact same username in it.
When I was in the online dating scene, there was a man who messaged me. I decided to search for him. His username came up in Google results. I put my skip tracing skills to use and found out his real name, where he worked (he was an attorney), his address, and that he was actually more than 10 years older than his dating profile said. Knowing I didn't want to be involved with someone who'd lie like that, I messaged him back and told him I wasn't interested. I called him by his real name and also made a vague comment about his law office. His response to me was that he didn't know whether to be offended or to hire me at his law firm.
Use A Username You Haven't Used Anywhere Else Online
With that being said, someone could easily find YOU online if you use the same username on your online dating site that you use anywhere else across the world wide web. Make sure it is completely different from any name you've ever used. Also, don't use the beginning of your email address. If your email address is MyInfo411(at)yahoo.com, don't use MyInfo411 as your username. People can find you that way. In this crazy world we live in, you don't want just anyone being able to find you.