Every conceivable means of trying to hire someone produces a deluge of résumés that someone has to sift through, most of them are an attack on logic and the english language. I currently find myself in a position of turning a mountain into a molehill, and I can't possibly read them all. So as an engineer I came up with a simple rule to reduce the load to a pile that I can then read through. The rule is really simple: If a specific technology appears to be key to the job posting and the résumé or cover letter doesn't mention that technology then discard it. For example, if there is a job for a Perl Developer, I would anticipate finding the word Perl in the résumé, and if it isn't in the résumé there had better be an extremely interesting story in the cover letter as to why you would apply for this job without the benefit of any knowledge of the main subject. The story wouldn't even be that hard to write. An example would be, "I have been coding since I could reach my Dad's TRS 80 and while I haven't worked in Perl before, I have worked in several different languages and am confident that I can become proficient in Perl development in a short amount of time." Sure that alone won't get you an interview, but at least you put some effort into applying for this job, and maybe you even bothered to read the title!
Applying this rule afforded me some time to throw together this posting, because it eliminated about 75% of the applicants to date. Just because monster or dice or whatever job search engine out there gave you the ability to set up keyword agents and spam your resume to the list that matches doesn't mean you should use it. It is an insult to the person who is sorting through the applicants, you are effectively saying that I can't be bothered to even read your job posting, but I want you to read my résumé.
An even simpler way to reduce the mountain would have simply to throw out all the applicants that didn't bother to include a specific cover leter. I didn't yet apply this rule, but I may soon. If you can't spend time trying to convince me why I should interview you, or even extending the courtesy of a short introductory note, then why should I bother? By the way if you try to make a point that you are good at communicating on your résumé but don't include a cover letter, then I must assume you are prone to exaggerate your abilities.
The point of all this is, if you are trying to find a job put some effort into it: do some research, and only apply for a job if you understand the ad and think you meet the requirements.