This is the same thing people accuse Facebook of and nobody has convincingly proved Facebook does it. I despise Facebook as much as the next HNer but I am loath to make it seem more capable than it is. Likewise with Discord, I sincerely doubt they can handle combing through voice + text data to build profiles of users, and I'll keep that stance until someone convincingly proves that they do.
Natural Language Processing is literally a major wing of AI development and data science, but even that isn't really necessary. Matching text on ad-based keywords has been going on since fucking About.com.
