Most apps that call themselves news readers have a recommendation layer. You add sources, but the app decides what you actually see. Which articles surface. In what order. How often. The feed looks like your choices. It's shaped by something else: your click history, what people like you read, what keeps sessions running longest.
Slow Web doesn't do any of this. You add a feed, it publishes articles, they appear in your edition in the order they were published. Nothing re-ranks them. Nothing weights one source over another. Nothing decides that an article from last Tuesday is more relevant to you than something published this morning.
Because there's no algorithm, there's nothing for your reading to feed back into. Slow Web doesn't track which articles you open, how long you spend on them, or which ones you skip. There's no reading history being built. The feed you see tomorrow isn't shaped by what you clicked today.
What you get instead is a direct line to the sources you chose. If a site you follow publishes something, it's in your edition. If it publishes twelve things in one day and you set a per-feed limit, the most recent twelve appear. The editorial decision is yours: which sources, how many articles, what order within a channel. After that, the feeds run on their own schedule and you read what they published.
That's what user-controlled means in practice. Not a preference panel buried in settings. The sources are the product.