Zetsu and Izanami
Several people have theories about what Izanami is after the last chapter. I won't bother to offer my own alternative. So far it seems like the most likely explanation of it's mechanism is that it records a segment of battle and then allows that segment to be replayed on loop.
The word "record" reminds me of zetsu, who has been asked to "record" several battles in the past.
We know that Zetsu is some kind of genetic experiment, where the white half is clearly influenced by Hashirama's DNA, has a low level of wood release technique, has several plant-like attributes and techniques, and who appears to have been fed chakra by a large plant which was derived from Hashirama's DNA.
However, the black half is a little bit different. We haven't seen any clones of the black half. We haven't heard the black half described as having wood release or of being related to Hashirama in any way. I've heard several people suggest that Black Zetsu is somehow related to Madara Uchiha, or otherwise has Uchiha DNA instead of Senju DNA.
IF Black Zetsu is Uchiha-based and IF his recording is performed by a (possibly modified use of) Izanami, we could start to see this technique playing out in future chapters. Black Zetsu could force battles to repeat, such as the battle in the valley of the end between Naruto and Sasuke. When Tobi says he will "force" Naruto to fight Sasuke, this might be what he is talking about.
Notice also that Itachi's eye only closed AFTER Izanami recorded the battle, right before he put it on loop. This could be why Zetsu hasn't gone blind from all the battles he has recorded.
By trapping some of the most powerful fighters into endless looping battles in Izanami, Tobi would be able to capture them easily.
This theory is a bit of a stretch, but what we know about Tobi and Zetsu is that they are obsessed with certain blood lines and certain clan attributes and feuds. This seems to me like a natural extension of that. Itachi using it against Kabuto is a good way to introduce us to the technique so when Tobi starts using it we will know what he's talking about.