Merit system has helped, has changed the forum more than one month after its launch (in January). Nevertheless, somewhere in the forum (like Altcoins ANN/bounties, or even in Meta), there are still shitty-posts/topics created by spammers because those two reasons.
1) Spammers believe that they can get merits from spamming Meta, begging for merit sources with their shit (repeatedly). Overtime, they will recognise that they won't earn merits that way; then they will stop (and might start new strategy, lol).
2) Spammers, again, think that Meta board seems to be the easiest section to catch attention of higher ranked users, who can send them sMerits. Again, overtime, they will realize that higher ranked users will become more and more strictly when verifying post-quality before sending their sMerits. It due to two other factors, merits will be more scarce overtime; and if some spammers keep ranking up by their shitty tactics, merit senders will tie up their rules before giving away.
As Vod said in above thread, merit senders should give strong signals about point of view.
To sum up, merit system will continue to change the forum, both old good users and spammers (some will leave the forum, some will adapt to survive - I hope they will become good users in the forum due to effects of merit system; not innovate new strategy to rank up and spam.)