Yes, he quit over a disagreement about the precise location of the office. Definitely camel's back. Reddit has been through a lot of turmoil recently:

1) Moving entire remote company to SF

2) Raising $50 million

3) Many employees, sometimes key, quitting

4) Celebgate

The disagreement over Daly City/SF probably just put Yishan over the top. Since then, more turmoil:

6) Yishan quit

7) Entire company actually performs the relocation

8) A new office is found and moved to in SF

9) New executives take over. Probably some power struggles which I didn't see.

10) New product plan is laid out for 2015. Does not include cryptocurrency.