The first is that you are you, always you, no matter where you are. There you are on Instagram, on Pinterest, on Twitter, on LinkedIn, on Facebook and Reddit. You are there in the comments, you are there in your vacation pics and the memes you repost. The news stories you share and the comments you like, oh the comments.
People get to know you as an amalgam of all of these things. And while your quirky personality may have been a professional liability five years ago, it is a tremendous asset now. You should absolutely be yourself, and the more you are yourself the happier you'll be as well as the more employable.
The second is that social media is more and more realizing its capacity as the ultimate crowdsourcing tool for reason. By that I mean, information that is useful will bubble up to the top. If it is logical, helpful, rational it will rise. If it is emotionally raw in an engaging and meaningful way it will rise. If it brings people together it will also rise. On the other hand if it's irrational ranting and raving, propaganda and hate, or if it's self-indulgent trash, it will sink.
Nowadays people look you up online. You have no choice, really, but to be yourself.
All opinions my own.