It has been discussed on the Meta section and, of course, can be interpreted under two different points of view:
1.- This is a new kind of farming-accounts system. This is easy: you create anything with your alt account, merit this and then delete the post, for you will never be able of being accused of being merited by writing garbage. I'm afraid it is efficient for those with alt-farmings-accounts.
2.- From the last month mods have been really actives and they have moved/locked/erased many posts, including some with useful quotes. Maybe many merited posts were deleted as a collateral damage, but we will never know.

Some users are talking about losing the merit you had if the post is deleted, but this is not implemented yet. In my case, I rather prefer for them to implement a "Report possible merit abuse" button in each profile section, for merit is not moderated and I think it should be. Many merit accusations have no fundament, for instance in local boards, where there are fewer people, they merited each other, yes, but, as I have seen, the merits are well-deserved in many cases, and there is not farming at all (for instance, the spanish local section, in which you will find many useful posts made by few, and of course, they merited the quality). That's why the profiles should have this kind of button, and merit system should be moderated due to the increment of farming activity.