Twitter is making some hiring changes. According to TechCrunch, Dick Costolo has taken a position as Twitter’s new Chief Operating Officer. Dick is the co-founder and CEO of Feedburner. Costolo left Google (which purchased Feedburner in 2007) left Google in July.

Costolo was an early investor in Twitter and, according to Arrington, has “actual experience building scalable infrastructures.” Twitter’s existing operations head, Santosh Jayaram, will most likely remain with the company and report to Costolo.

Twitter is smartly expanding their senior staff, including a new General Counsel and new people to work with their Search capabilities.