There's always the first one which each and every one of us started our social media journey with.
It's the first one which you created an account with and started engaging with others online. Do you still remember the first social media site you used?
I first signed up to Facebook in around 2008 or 2009 I think. I think I had briefly visited MySpace before Facebook, but I didn't sign up until much later so that doesn't really count! A couple of years after Facebook I discovered Twitter and then that became my main social media profile as I sort of fell out of using Facebook and found more of my friends and more interactions over on Twitter.
Myspace was the first one I used! Honestly it's better than Facebook ever was, the fact that you could customize your own profile and add CSS edits made it awesome! It sucks that the website was never properly backed up and lots of data was lost. I had a video on there that is lost to time, including some pictures too.