Audience Appeal
The resume is a kind of advertisement for an applicant's future abilities based on past experience. Advertising writers spend thousands of hours and dollars determining how best to present their information to a specific audience in order to sell a product. The desired outcome of any advertisement is to get the viewer/reader to go out and take a risk by spending money on something. The desired outcome of a resume is to convince an employer to take a risk and grant an interview. Don't forget, employers often have many more applicants than positions available. Those who make their own document stand out by determining why it needs to be written and tailoring it to the needs and priorities of the people reading it are more likely to receive an interview.
Also like an advertisement, a resume offers the writer a finite amount of space to accomplish its goal. Most resumes are no longer than a page to a page and half. In such a small space, language and form are amplified, making them the two most important tools for appealing to its audience.
It pays to spend time considering the layout and design of the resume as well, to insure its readability.