Here’s a good definition of what a brand is. 

The most successful brands, or at least the ones everyone emulates, successfully use design to produce an emotional coherence that spans content to product to experience. Think Apple or BMW or Chanel. Not everything has to look alike, but it all has to feel alike. Whenever we encounter them we get that familiar brand sensation. That tingling tells you it’s working.
Michael Rock in the NYT Now

I think a lot about the “self-branding” that each if us does when we use social media. Rock goes on to point out the obvious sort of post-modern, dystopic view of our overly-virtual lives—we create these brands as artifice, desperately seeking emotional connection from emoji and emoticons.

But I think there’s a less depressing view: The connections through these social media are an additional and richer layer to our interactions. We still have human contact, but now we have even more ways to sustain those IRL relationships. 

As for the branding, I think part of that is just trying to understand how we are perceived through digital media. It’s a new thing, and it’s still evolving. Haven’t we always been branding ourselves IRL? Now that we’re representing ourselves in digital form, maybe we have more to learn from those “successful brands” who’ve had to do this for much longer through their products.