Researching employers is a critical part of your job search. Research assists you in learning more about an organization, contributes to your preparation for each interview, helps you prepare stronger cover letters and ultimately make informed decisions.
These websites will give you more detailed information about the employer, such as financial information, competitors, product lines, etc
These websites will help you assess what's going on in that particular employer's industry. Information obtained here can be a great asset during the job interview. It will help you identify your contributions to the employer's efforts to meet the challenges that exist in their industry.