Bubbles
A commonly perceived problem in the social media world is that of “bubbles” or “echo chambers”. That is, you (dear user) wind up in a space where your preconceived notions are reinforced by all the input you're receiving, leading to increased polarization and lack of balanced perspectives.
One criticism leveled against small social media, or what I've labelled “individualist federalism”, is that it's basically a pre-built echo chamber. You have folks like me running a single node and I choose peers who produce the content I want to see which has a certain slant to it (in my case, some combination of technical geekery and anarchism). If you (dear user) join my node, you get a dose of technical geekery and anarchism but you don't get much gardening advice because I don't peer with nodes that produce gardening advice (not by choice, though – send me your nodes that discuss gardening!). That's a bubble of sorts.
Where I dispute this perspective, however, is that you can easily have accounts on different nodes and even different networks. If you're dissatisfied with the lack of gardening advice in my federated network and you find a network with the gardening advice you crave, you can just go sign up over there and get your gardening advice fix. The fact that no single node owns the network (unlike, e.g. Facebook owning the entire Facebook graph or same for Twitter, Instagram, etc) means you can engage with diverse networks with a single technology to craft the experience to your taste.
This is very unlike specifically Facebook and YouTube which are transparently making decisions about what content to push to you, which is transparently motivated by ad spend by people with an agenda to get you to think a certain way (even if their agenda is no more nefarious than just getting you to consider buying more Oreos, but Cambridge Analytica proved this same idea applies to political thought-shaping as well).
So to summarize, I suppose I'm not disputing that small federated social networks produce bubbles. Ultimately you are always going to be subject to a limited set of information. The key distinction for me is that you, the user, get to shape the bubble to your tastes rather than having it shaped for you by ad-fueled algorithms.