@paulgc@mastodon.social nope! Replies are only received by your server if they're sent them by the person replying.
On Mastodon this usually takes the form of a mention. When a user is mentioned on Mastodon, they are de facto addressed as well.
In turn, that means the activity is delivered to those addressed users.
If a mastodon user replies to your post but does not mention you, then you will not be receiving that reply. (I think.)