So these are the numbers of people who --> could <-- have seen the hashtags you've used, hashtags being the primary way people find posts from people they don't know
OK: this all depends on if they're --> following <-- those hashtags (which I guess being included in this stat would imply) and if they're paying any attention to them
I don't know what this tells you, but that's a pretty good number of people from the times I've looked up hashtag traffic in the past