There’s a myth that social media apps sell your data which isn’t true but is related to the truth. In reality, almost every company you do business with from telcos to grocers to banks sells your info to other businesses.
However until social media, this just meant junk mail.
Social media changed this by going from retail stores sending me physical junk mail about sales because my grocer sold them my info to seeing TikTok ads for T-shirts on sale for similar reasons.