People love lists. (Remember Moses and his two tablets?) An industry ranking system gives readers a pre-assembled "best of" list that ranks available options in a given topic area - and subsequently ranks high with search engines. A list, whatever it may be, presents you as an industry expert, and gives your prospect a helpful tool they desire or need.
Rankings can be determined by some objective, measurable means, or by subjective criteria Make liberal use of links to the listed resources Announce updates to the ranking system via blogs, Twitter, press releases, etc.