Did you read the OP (Opening Post) of this thread?   Theymos announced the new merit system and he explained why he was implementing the new merit system.  He also made a few other posts giving further rationale behind his thinking for implementing this new merit system.

Ultimately there is no exact objective standard for getting merits, and so therefore, some members are going to like your posts for differing reasons, and some of those members might have smerits that they are willing to give to your post, if they believe that you are adding something for them or maybe if you have a kind of pattern of providing information that they believe is useful ... so there could be a combination of your attempting to learn by reading the OP but also that you are engaging in various threads and posting in ways that are potentially useful and helpful to others.