@luiscarlosgonzalez
It will first display main subjects, then by clicking on a subject, you will have comments.
At this state, nothing is federated with your instance.
But if you decide to make an action on a Lemmy message (comment, reply, boost, fav, etc.), only the current message and the Lemmy account (author) will be federated with your instance.
So, it won't overload your instance.