-1: The potato rating is supposed to be the "Silly Rating", imo. We don't need another annoying rating people can spam.
The potato rating may be funny, but it's not used on a post because people find it funny, it's always used when someone thinks that a post is stupid or something like that. A funny rating would be there purely for posts that are funny.
Nah, it is wrongly used that way imo. Or it means some of the three: Funny and/or Silly, and/or Stupid.
In the context of the rating, potato usually means low-quality, or stupid - basically only negative things. On other parts of the internet you may have seen people comment on a video saying 'this must have been filmed with a potato', I honestly can't think of a scenario in which someone would use the potato rating to say that a post is funny.
Perhaps you could take just a few minutes and search thru the several other times this has been suggested and see what the response was from our server owner? He has explained this clearly more than once I believe.