Chicago Tribune
If you're wondering where all of the candidates are spending the $150 million they've raised so far, a lot of it is going into operations like this. A couple highlights:
[*] 31 state-wide field offices, each of which he needs to pay rent for.[*] Tracking each known supporter and calling each of them every three weeks.[*] Conducting a dry-run for caucus night in December by turning out all of the supporters for house parties.[*] (Probably) putting a campaign worker at every precinct to hand out banners and organize.