Ask most people running documentation for a plugin or mod which page needs the most work, and you'll get a shrug. They know a page exists. They don't know if anyone reads it, whether it answers the question people actually have, or if it's the reason someone gave up and asked in Discord instead. Without data, updating docs turns into whichever page you personally remember being annoyed by last.
A thumbs up or down changes the whole workflow
A "was this helpful" widget at the bottom of a page is a small thing that produces an outsized amount of signal. It's not a survey, it's one click. But once fifteen people mark your config reference page as unhelpful, you know exactly where to spend the next hour of writing time instead of guessing.
Adding an optional text field ("what were you looking for?") turns a thumbs-down into an actual reason. Half the time the fix isn't a rewrite, it's adding one missing example or clarifying one config key that everyone happens to misread the same way.
Pageviews tell you what people are actually reading
The gap between "pages I think are important" and "pages people actually open" is usually bigger than expected. It's common to find a heavily polished getting-started guide getting a fraction of the traffic of one plain command reference page, simply because that's the page people are searching for. Once you can see this, you stop over-investing in pages nobody opens and start protecting the ones carrying most of your traffic.
Search queries with no results are a to-do list you didn't have to write
This is the single most useful thing analytics gives you. If your search logs show "permission node list" searched forty times with no page matching well, that's not a hypothesis, it's a direct request from your own readers for a page that doesn't exist yet. You don't need to guess what your community wants documented. They're already typing it into your search bar.
Comments close the loop
A feedback score tells you a page has a problem. Comments, especially threaded ones tied to a specific page, tell you what the problem actually is. A comment thread under your install guide asking about a specific version conflict is worth more than a dozen generic "please update" messages, because it's tied to the exact spot in your docs that needs the fix.
What this looks like in practice
Nectory bundles a feedback widget, page and space level comments with a moderation queue, and pageview plus search analytics into the dashboard by default, so this doesn't require wiring up a separate analytics tool or building a comment system from scratch. You can see the full breakdown of what's tracked on the features page.
The teams that keep their docs genuinely current aren't the ones with the most writers. They're the ones who know which page to fix next without having to guess.