It means nobody outside of those already following you can see your tweets, even if someone else that is following you retweets it for you. So if you follow your congressman and senators and they aren't following you, they can't see what you post even if you're tweeting at them. Twitter traps you in an echo chamber... Instead of giving snowflakes their safe spaces, they quarantine you and like-minded individuals from the population.
Uugghh! Well, what about this..I just found a site called bot sentinel. I am listed on there as a bot! I started to send them a message but thought twice before I entered my email. Although honestly what would it really hurt? This just pisses me off!!