Here are some examples of how it can be used:
* "Eso de que te mudes me pone triste." (That thing about you moving makes me sad.)
* "No entiendo eso de la política." (I don't understand that matter of politics.)
* "Eso de ser famoso no es para mí." (That thing about being famous is not for me.)
Essentially, "eso de" introduces a topic or a concept that the speaker is referring to. It can be used to express a feeling, opinion, or question about that specific thing.