Rank? Bah, humbug!
Very well said, Kevin and Magma! I agree wholeheartedly with both of you: no one ever won a match by flashing his/her certificate, and ultimately it's not your "rank" that matters, rather it's the effort YOU have put into your training to come closer and closer to the spirit of Budó.
I may be wrong on this (so please correct me if I am), but "ranking" and "recognition" are basically fairly recent concessions made to the western mindset by the different Budó-ryu, to provide for the west's "need" for an "objective" measure of a student's progress in any particular Art; as opposed to the student refining his technique, indifferently of any consideration of "rank" in the essentially competitive western mindset, and the refining of his spirit being the ultimate goal.
Thus,the issue of recognition of "rank" among the different schools arises and totally screws us up. In the end, the whole "My style is better than yours and I'll duel with you to prove it!" boils down to a whose dad can beat up whose dad, who can pee farther or whatever.
In ancient times, duelling had an important purpose: recognition as a WARRIOR kept you employed and fed. It wasn't a question of Art, it was a question of reputation, honor and employment. Of course, if you had an effective style you could teach it and maybe win the favor of a powerful daimyo if you taught his soldiers a good way to fight.
Obviously, nowadays, duelling doesn't have any useful purpose, and it winds up being a bragging match. I've said before: it's not the Art that wins a match, it's the opponents that win a match. If a Ju-jitsuka beats a Karateka in a match it doesn't mean that Ju- jitsu is a better Art than Karate. It only means that the Ju-jitsuka was a better fighter and NOTHING MORE.
Having said that, I do believe that "ranking", taken with a large grain of salt, does have some merit. For example, it gives the beginning students a more concrete goal to reach, along with the initial psychological effect of "rewarding" effort, or "positive reinforcement" of the beginning student's training. Furthermore, if handled properly, it institutes a reasonable curriculum of fundamentals and waza that the student masters as he "rises" through the ranks and leads logically from the easiest techniques to the more advanced ones.
And having said that, please remember that we no longer live in the violent world of Japan's feudal period, thus Martial Arts are no longer "necessary" to survive in our society. Rather they are to be used as a vehicle to better ourselves as earnest, sincere, forthright and useful human beings.