Last few pages of this topic: [Upgrade!] So.... on which board did you earn (or spent) most of your (s)Merit? shows contributions in local boards are recognized and merited more frequently compared to same members' other board contributions.
When local boards' merit sources are effectively recognizing right posts with respect to their countries' BTC adoption levels and BTC based business levels, why not we have board-specific-merit-sources for all other boards to entourage the right contributions and high quality posts.
For example, an active gambler will be able to assess right contributions in gambling boards and same applies for an economist in economics and for a trader in speculation and trading discussion boards.
A student may learn multiple subject at a time but his teacher must need to be an expert in one subject to teach him one particular subject. Similarly, we may post across the boards but it could be recognized only by an expert in the same field.