I would argue that with 2 options (Add & Subtract) allow for interaction to portray satisfaction that you have with said user. Sometimes it's positive, sometimes it's negative, but there are circumstances in which someone is an outright troll. Which would be a positive influence to label those people.
Now I would further provide that the current reputation system in place on vbulletin allows for a user to up/down vote someone as well as comment on why they chose said reputation. Further I would provide as an example of said popularity, that the current system I explained above has been used to make a total of 91,061 reputation comments -98,701 total votes - 55,394 plus votes , 43,307 neg votes and this is where users can only + or - each user only once
I believe this would allow us to further mark our users based on their contributions. As long as it's relevant, it will get used most of the time.
I also would not mind being able to "clone" the like button and rephrase it for specific sub-forums. I.e. in a beginner/newcomer sub-forum, where typically questions are asked and answered, it could be worded "thanks", or an achievements forum, it could be used to congratulate someone with an achievement.
A mod will need to be requested for a reputation system or a mod that will enable users to be marked based on their contributions or that does anything other than a single click like. XenForo has a 'like' system and we all know how to use it. That is what it is.
Has there ever been any discussion about adding more single click options in addition to 'Like'? Might be interesting to offer one or two additional options and label them however you want (e.g., '+1' or 'Me too'). These wouldn't even necessarily need to be a part of the status system, though that would also be an interesting option.