Though as has already been said ranking systems can be advantageousin that that
they may help new readers to distinguish people who give solid, credible advice from
those who don't, the reactions to one such person by other posters often quickly
have the same effect.
As something of an aside it's also fascinating how often the value gleaned from a
post, any post, may be more dependent on the comprehension and insight of the reader
than that of the original poster or their intentions.
Also, where there's a system like that there will be the temptation for some people
to abuse it, and one person with a grudge can have a surprisingly big effect- the
result being that there's not guarantee the results of reputation function would
even be accurate enough to be of practical use.
But this aside, my opinion is that I am inclined to vote against the reputation
system. However though theoretically it has its advantages and disadvantages on a
practical level, by the very nature of social systems an idiosyncratic hierarchy
both of people and modes of thought will probably form and be apparent to some
degree at least anyway, whether we recognize and quantify it numerically, with stars,
or not at all. Whether this is a good or a bad thing depends of course on where you
sit in relation to it.
The thanks or like system idea seems like it could work well, though.