That is a higher standard kind of rule compare to other managers which is something can be pressured to get at least a merit every week.
While it can be a tool for improvements of post quality, on the other hand it will also open for merit exchange or just merit abuse lately.
The rule it's self is still subjected to change according to Yahoo. And he also offered to do post review for any members that didn't meet the requirement, at least it will help to curb merit sharing. Although this rule will be hard on members that post only on Gambling board since merits are hard to come by on that board