In recent months, the Stack Exchange has shown that it's not really community run anymore. My concern started with the capricious de-modding of Ceillo for simply asking questions about a proposed Code of Conduct change before it was enacted.
The recent firing of Robert Cartaino and Shog9 only further show how out of touch Stack Exchange is with the community. They just don't seem like they care anymore about what meta users think.
Occasionally, they might give an opaque statement, or even say something that gives people hope that things might be resolved, but so far no real progress has been observed.
I've considered resigning for a while now, and I've been thinking of the possibility that moderators might resign as something to leverage in order to get Stack Exchange to right their wrongs. So far there's no sign of progress, so, in order for that leverage to have any teeth, I have to step down.
I've already contacted Stack Exchange to let them know I'd like to step down. From the sounds of things, it might take them some time to take the diamond away. I hear that they're short on few Community Managers these days.