If someone says "I wish X had feature Y", answering "then X isn't for you" does not contribute to the discussion. Products can change and feature requests shouldn't be dismissed on the grounds that the feature doesn't exist yet.

In this case it certainly could, and is almost already implemented (in the form of both the "hashtags" and "topics").

I could see Following topics from a person becoming a feature. It's a natural extension of the current feature set.