This advice really relates to all resumes in the era of the keyword-searchable database, but it's especially important for e-resumes. Job-hunting today increasingly revolves around the mysterious world of keywords. Employers' use and eventual dependence on keywords to find the job candidates they want to interview has come about in recent years because of technology. Inundated by resumes from job seekers, employers have increasingly relied on digitizing job-seeker resumes, placing those resumes in keyword-searchable databases, and using software to search those databases for specific keywords that relate to job vacancies. Most Fortune 1000 companies, in fact, and many smaller companies now use these technologies. In addition, many employers search the databases of third-party job-posting and resume-posting boards on the Internet.
The bottom line is that if you apply for a job with a company that searches databases for keywords, and your resume doesn't have the keywords the company seeks for the person who fills that job, you are pretty much out of luck.