When I had my Merit source application open, I made it a point to never Merit any of the posts in that thread.
Actually I think that's how it should be ethically and technically. I thought that we can merit a post if they find that your post is useful and sometimes a hilarious one.
Yes we can unless that thread created for the "Application for Merit source" . That's how I sees that. Sometimes I can be wrong. Quote
I think its just a Filipino culture to show some kind of appreciation 
I think you can give your appreciation to the Merit source applicant by giving few Merits for his thread, but the best appreciation can do by the Merit source applicant to the community who supports his application is not giving any sMerits for the replies of his thread. In that way he/she can enlighten the forum members that he knows about the value of Merits and how it should spend where actually deserved.