At its best, twitter was group texting, but in public. its evolved into a semi-broadcast form with the expectation that many will read and few will engage, and in both twitter and mastodon the tooling is built for that.
within that, you follow people because they produce content you want, or because you intend to interact. Hashtags are there for topics you are intersted in so you can consume in a more ad-hoc way
Not an expert, but I gather the power of the aod is too little to cause burn in