***I know I'm over-analyzing the following, I just like to showcase interesting points***

Here we see Black Zetsu (denoted by the difference in font style) answering Tobi's question:

http://www.narutobase.net/manga/Naruto/396/7

Tobi's Question: "Did you make sure to record the whole thing while you watched?"
Black Zetsu's response: "Relax. I got everything."

This tells us the following:
-Black Zetsu has the ability to record events (most of us already knew this, I know).
--In addition to the previous: Black Zetsu can switch between "Viewing Mode" and "Recording Mode" at will.
-Tobi was very anxious (almost desperate) to have the Sasuke vs. Itachi fight recorded; so much that he needed to be told to "relax".

After this, Tobi states: "I think I will. I'll relax and enjoy the viewing later."
From this we can predict the following:
-Tobi finds some sort of "enjoyment" in watching major fights:
--Naruto vs. Sasuke: http://www.narutobase.net/manga/Naruto/234/18
--Sasuke vs. Itachi: First link of the thread
--Killer Bee vs. Kisame: http://www.narutobase.net/manga/Naruto/487/13
***If I missed any major fights that Black Zetsu was "recording" (besides him versus Nine-Tail Chakra Mode Naruto), please state them as a thread response.***
-Tobi can watch these recordings through unknown means (perhaps by "hooking up" to the "Zetsu Tree Information Network")

Is there a purpose for these recordings? Does Tobi like making a serious timeline of events and a "How the World was before Infinite Tsukuyomi" movie? Or is he just a junkie/fanboy for main character fights?

And so I leave you with this "interesting" thought:
http://www.narutobase.net/manga/Naruto/487/16
But I thought Zetsu's didn't need to eat to stay alive....? o_O