Yahoo! Finance aggregates information on publicly traded companies from a number of sources and presents them for free for your use. The Sector List, a section of Yahoo! Finance, divides businesses into their respective industries (similar to NAICS codes). Each industry has links to companies and in turn to individual company profiles. The company profile lists information on the number of full-time employees, the names (and sometimes the salary) of key executives and their top competitors. You can use this information to knows

- how large a company is and if it is worth targeting
- a company's closest competitors / similar companies that you can target
- the salaries of key executives in a company and much more...