Advice from Human Resources at Berkshire Capital:

Students should make themselves very familiar with the company and the history of that particular company. There is an abundance of information located on the Web site of each company. Students should also follow instructions very carefully. If we request a writing sample, transcripts, SAT scores, cover letter and resume that’s what we expect from each student. All the required materials are what we use to make our decision on who we want to interview.

The main problem with over-researching is that it steals from other activities: namely, meeting people directly.

Since job seekers are often more comfortable with screen time than face time, they will artificially extend their computer tasks to delay other steps, such as networking. When they do, they miss out on a fundamental truth: After a certain point, more research does not pay off, but more networking does. This coincides with statistics showing that most jobs are obtained through networking.

The caveat: When the method of research is primary-source–when you speak directly to a person and ask questions–you are simultaneously building contacts in the field. This is one research strategy that can never be “overdone.”

College students and recent grads are forever being told to research companies and/or jobs very thoroughly. So how can they know how much research is appropriate and how much is too much?
Research should be appropriate to the stage of the job search. Here are some examples:

You’re considering specific companies to work for but you haven’t made any contact with them.
Start with a low level of research: just enough to understand their primary products or services and their mission. One visit to their Web site should cover it.

You’ve scheduled to meet with someone from that company , either for a job interview or for further information.
You need the next level of research: reading articles about that company and possibly checking out competitors to understand the environment they’re working in.

You have a job interview.
In addition to the steps above, also try the product, or at least find customer blogs with comments about the company. Very serious candidates might also interview vendors and company contractors, as well as current and former employees.

Adapted from Employer Insights, Campus Career Counselor, January 2008