Which subreddits actually say it?

This searches our own collection, not the whole of Reddit. Lidar reads a set of communities every day and keeps what it finds, so the numbers here describe the posts we have actually seen rather than everything ever written. That makes the tool narrower than Reddit search and more honest than it, because every figure on this page comes from a row in a table we can point at.

It is also a keyword match, which is the part worth being careful about. A post that says a word is not the same as a post that wants your product. Somebody writing about churn might be bragging about reducing it, and somebody looking for an alternative might be looking for an alternative to something you have never competed with. Reading the threads is the only way to tell, which is why the results link straight out to them.

The useful output is not really the list of threads. It is the shape of the table above it. If one community holds most of the mentions of a word that matters to you, that is where your market is talking, and the community profiles will tell you whether you are allowed to say anything there. If the mentions are spread evenly across a dozen communities, the word is probably too generic to build on and you want a more specific one.

For the phrasing that tends to work, the guide to Reddit search operators covers how to run the same idea against Reddit itself, and reading buying intent covers how to tell a real signal from a word that merely looks like one.