After reading all the feedback I have scaled this proposal back to a very limited trial run. Here's my current working draft:
TalkBoard recommends trial of a per-post reader feedback button labeled "I found this post helpful ^" in the Trip Reports forum in order to give readers a quick way to say "thank you" other than cluttering the forum with a "+1" post.
At this time TalkBoard makes no recommendation for wider use of this or any other positive feedback buttons.
Subject to implementation constraints, TalkBoard would prefer that: (a) only logged in members have the capability to provide feedback, (b) feedback totals be visible to all readers without further clicking, and (c) the handles of the individual voters become visible to all readers via a further click or mouse hovering.
TalkBoard recommends AGAINST implementing any new negative feedback feature anywhere on FlyerTalk.
It seems like there isn't a strong demand for any implementation, so why insist on this at all?