The reason I don't understand how this stops account farmers, is consider this:
Assume an account farmer with an extremely large number of accounts has roughly the same number of mean Merits per post as a normal user.
If he gets 100 Merits, he also gets 50 sMerits. He then redistributes these 50 sMerits amongst his accounts. Assuming he has planned this well, he should be discreet about it, and in the end he'll get 25 more sMerits to distribute.
Once you calculate the entire thing, you realize that for every Merit the account farmer receives, he gets close to a total of two Merits across his entire group of accounts, once you account for sMerits.
Counterargument:
Also it will be pretty easy to detect such collusion as everyone can see who you give your merit points to.
I think this might just be the Toupee Fallacy.
You only ever notice that bad colluders are performing collusion, so you assume that everyone who colludes will be readily noticeable.
When collusion goes well, and with the merit system, I think it might be easy to hide, you will not notice it... and hence assume that the only people who collude, are the ones who obviously collude.
So in the end, account farmers get twice the merit across their accounts for the same quality of posts.... which is an issue, but I guess it's not the worst.
It's a good point to discuss with. In some cases this merit sometimes can be abused of course. I am pretty sure that theymos and other admins have already discussed this type of issues. It will then eventually improves the merit feature by adding other functionalities. I guess it still goes back to the role of the moderator. Any proven circumstances of merit abuse shall be reported and investigated. I was just thinking tho if the main account of spammer can really abuse it since there are limitations in sending a merit and if you are not receiving one then you surely cant share it as well