We've featured word cloud services like Wordle and TagCrowd before. When applying for a job, it could be useful to dump the entire job document or selection criteria into one of these tools, just to quickly identify which specific words they're targeting.
It's already recommended to use the same words the company uses when they advertise the job. It's also a good idea to browse the company's mission statement, and incorporate that terminology as well. So while it's probably not a good idea to use this as your only tool when writing your resume and cover letter, it can help -- especially considering some employers love their long, drawn out job documents. I'm looking at you, any government job ever.
We've suggested using this technique on your own resume before, so this is basically the reverse. Using generic words that supposedly everyone likes such as "diversity" or "punctual" could be fine, but there might be some you should get rid of.
Those applying for large swathes of jobs might even consider dumping several job documents into one word cloud, and constructing their documents around that. As stated above, it should be considered as just a tool, not the whole hog -- but if you go this route, pay close attention to the smaller words as well. The cloud will automatically cut out meaningless words such as "the", but other useless words can rise to the top, such as "channel".