The 2015 blackout or AMAgeddon was an event where moderators showed their dissatisfaction with poor admin communication by taking several major subreddits private, in a work stoppage of sorts. It gained a lot of international press coverage, and generated support for a change.org petition calling for Ellen Pao to resign.
- July 1 — (it's unclear if this is related) An AMA with Jesse Jackson goes badly and is widely criticized.
- July 2 — Victoria Taylor (/u/chooter) is fired from reddit. She served as a helpful liaison between the moderators and the admins, particularly for celebrity AMAs. The reason for her firing was never disclosed, which is standard corporate HR practice, however, there were rumors circulating. 
- July 2 — Initially /r/IAmA and a few other major subreddits go private, followed by a large number of subreddits joining in solidarity. They point to the lack of communication surrounding Taylor's firing, as well as a general lack of communication from the admins. 
- July 3 — Major subreddits begin opening back up .
- July 3 — Former admin /u/Dacvak does an IAmA, but quickly deletes it. (archive, archive2) It was believed he deleted it because some of his statements could have gotten him sued. Users elsewhere focused on his allegations that he was fired because he had cancer.
- July 4 — A conversation between admin /u/kn0thing and the /r/science moderators is leaked. It shows some problems in communication between the admins and moderators. However, followup by the /r/science moderators indicates that it was only a momentary breakdown in communication.
- July 6 — The admins post an apology, but the user response is mostly hostile.
- July 10 — Ellen Pao resigns as interim CEO, replaced by the original CEO, Steve Huffman (/u/spez).
Discussion in various subreddits at the time: