Questions being tweeted.

Question

How is it decided which questions get tweeted by the stack exchange programmer twitter account?

http://twitter.com/#!/stackprogrammer

Is it a choice by a mod or just automatic every nth question?

Answer 1

It's algorithmically determined based on hotness, without repetition (no duplicates).

https://softwareengineering.stackexchange.com/?tab=hot

The (mostly) complete list of twitter accounts is here:

http://blog.stackoverflow.com/2011/01/twitter-question-feeds-for-stack-exchange/