Yeah, gnusocial and family felt like glorified RSS readers + feeds to me. That's what attracted me to the network initially. My own Mastodon/Pleroma client is built entirely around the concept of "feeds" (whether it be user, hashtag, conversation thread) and simple combinations of feeds (eg grouping together multiple hashtags to form a "topic" or multiple users to form a "group").
Mastodon should be the exact opposite of IRC imo. Hashtags or message threads can act as a simulated chatroom but generally speaking, the power of feed-based social networks is that they invert the traditional power structure, thus yielding more interesting content.