This is state-level data. The relevant agency varies from state to state. Many (most?) states allow searches of their database of registered corporations, but bulk downloads seem to generally require payment. West Virginia, for instance, sells this data for $12,000, plus $1,800 / year to keep the data updated.
- name
- ID
- type of entity
- jurisdiction
- date of registration
- status
- office location
- registered agent name and address
- number of shares
- Lead generation
- Information about attorneys, since they're listed as registered agents
- Knowing location of businesses (Google, Yelp, Foursquare, etc., etc.)
- Track down the owners of otherwise-anonymous businesses (for journalists, citizens, etc.)
- OpenCorporates, a UK ODI-affiliated organization.
- Crump, a Virginia-specific effort.