Do you signup with the same username/display name on every web service?
Twitter? Instagram? Amazon? Myspace? Livejournal? That Beanie Baby phpBB forum from twenty years ago? WebMD? Goodreads?
If you do, I’d suggest googling that username if you haven’t done that before. There is a high chance you may see a rather exhaustive history of everything you’ve ever done across the web. And that maybe fine depending on your personal POV.
But it can also be a bit freaky. And, if you fall in the camp that finds such an expansive, public, one-click view of your personhood a tad uncomfortable, I have a solution for you: digital identity diversification.
The idea is quite simple1: choose a unique username per service.2
1Hat tip password managers.
2Obviously, if you divulge details about yourself or expose a different unique attribute (eg: your real email address) that will break said compartmentalization. Just a heads up.