There are three prepositions to use with the verb live when describing the location you live at/on/in.
What makes the situation here different is that in the previous case your location would be an actual/real one, where is it not the issue here.
So when someone wants to describe the idea that s/he spends all her/his time on a social media site, say Facebook for example. Then, what is the right preposition after "live"? As it is doesn't actually mean living, I'm putting it in a scare quotes to make sense.
I "live" on/at Facebook.
I think it should be "on" as it is followed by a social media platform after all, but the verb live makes it a bit confusing.