That resonates with me. I have a blog, and it's far away from being one of the big ones everyone knows about. I write for an imaginary audience, partly to help myself think through ideas by organizing them into words, mainly just for the fun of shouting into the void.
I've had a surprising amount of feedback from strangers who say hi or ask for a followup to something I'd written about. It's a little gift each time that happens. I can't imagine that anyone would care about something I had to say, and yet here's this real person who wants to have a conversation about it.