What? These days "most" large companies use a software to look for key words. this is one reason the preferred format is MS Word. After talking with several Headhunter/Recruiters, I have found that even if you have all of the pertinent key words with in your summary section, you also need them in "each" of you job duties for each job. Example; in the past 25 years, I have worked for several different groups within the same company. I basically many of my job functions were the same just different processes, programming languages used and EDA (Electronic Design Automation) tools that I created. So, even if you have the keywords pertinent to the job that you are applying for in you summary section you also need to put it in bullets under each job or company that you have worked for. Personally, I think that it is a bit of "word over kill" but if that is what they want that is what we must do. Not to mention the fact that more than likely these very same keywords will likely be in your skill section, too. For the most part, long gone are the days that people not programs first looked at your resume.
With keywords, look at the job description that you are wanting to apply for. If I were looking for a job programming
I will talk more about keywords in a later post on the format of your resume.