1. Search Engines
Search engines like Google are very useful tool for conducting company research. You can find company’s website and its overall online presence. Many public companies have a section on their websites specially dedicated to investor relations and often have their annual reports online and in downloadable form.
Twitter has a very strong search feature that can help you track down companies. You may or may not be familiar with the hashtag (#) search feature that targets specific tweets on the network. For instance, a search for the term “#companyresearch” will return the latest tweets about the company or you can target a particular company tweets by using their #tag. You can also follow company boards on twitter.
You can check the LinkedIn profile of a company, the profile of the members of the board, CEO, CFO and other employees. You can also join and participate in LinkedIn industry and job search groups.
Craft's goal is to provide context in a rapidly changing landscape and help professionals discover and evaluate different opportunities. It provides free, open information platform mapping, providing data on dynamic sectors, companies, teams, people, and open positions. Simply type in company name and get the results you seek.
Glassdoor is a site where employees and former employees anonymously review companies and their management. In the year prior to April 2014, more than 500,000 company reviews were submitted to the site making it a perfect tool for company research.
Careerbliss is another site just like glassdoor, where you can read company reviews and other information about their management.
You can add yourself as a "fan" of the companies that you are interested in knowing. Many companies, like Ernst & Young, use Facebook to connect with potential job applicants.
8. Job Search Intelligence
Job Search Intelligence or JSI is a great salary research tool for job-seekers, with a comprehensive set of questions to provide accurate compensation data. Currently its offering information on 480 occupations, within 560 geographic regions.
9. IRIN or The Investor Relations Information Network
IRIN or The Investor Relations Information Network provides a single point of reference for accessing electronic annual reports. Its a clearinghouse of annual reports, fact books, and press releases.
10. Corporate Information
Corporate Information had more than 350,000 company profiles. Its a great resource for researching companies and industries in the US and around the world. You can search for company and industry information or search by U.S. state or by country to find companies that operate within a specific geographic region.
11. Canadian Business Resource
Canadian Business Resource or CBR offers in-depth information and profiles as well as links to more than 2,600 of Canada's top performing businesses.
Allstocks.com provide links to all kinds of information about companies and industry analyses.
Inc.com provide a listing with a short description of the 5000 fastest growing privately-held companies in the U.S.
14. Better Business Bureau
Better Business Bureau provide informative links to companies that are members of the organization.
Forbes provides a comprehensive database of the 500 largest American public corporations as measured by sales, profits, assets, and market value.
Vault.com well-known for its insider reports on thousands of companies.
Web100's top 100 lists, top 10 lists, and other lists will help you in finding any information you want.