Just realised ive never once seen an ad on my twitter feed. i dont have twitter blue. is this normal?

I mostly follow celebrities and tech people (the few that are left on Twitter). Someone tweeted about seeing too many ads on Twitter and I realised I’ve never seen one. Scrolled back through my feed and there’s just no ads. I certainly don’t pay Elon any money, so why am I not seeing ads? (I don’t want ads, just curious)