Verizon announced today that they are buying (most of) Yahoo for 4.8 billion dollars in cash. Back in 2015, they purchased AOL for 4.4 billion dollars. This means that three different email receiving platforms are now owned by one entity: Verizon. It's hard to saay what becomes of the Verizon, AOL and Yahoo! Mail platforms in the future. Since purchasing AOL, Verizon seemed to continue to invest in the AOL mail platform, and some Verizon email users were transitioned to AOL infrastructure. But now that Verizon will own both the AOL and Yahoo! Mail email platforms, both of which I suspect are pretty robust, there could be some internal competition regarding which email platform ends up being the primary one used across all users. Or would they keep both the AOL and Yahoo! Mail platforms running separately? We will see.
TL;DR? Verizon now owns both Yahoo and AOL. Future impact to senders unknown, sit back and stay tuned.
Edited to add: Here's another take on how the consolidation of the two platforms could go, courtesy of Litmus's Chad White.