Broken Base: This is probably the best way to describe the multitude of divisions of fans and the subdivisions of these divisions.
Catharsis Factor: One of the reasons the game is addictive. Making a totalitarian hellhole that responds to diplomatic incidents with all-out war may not be morally acceptable, but it's plenty fun.
Gameplay Derailment: Nationstates stands out as a franchise whose methods of playing the game could almost all be considered forms of Gameplay Derailment. Perhaps the most extreme example is the inter-regional combat system that players have improvised out of World Assembly elections, regional ejection mechanics, and huge amounts of Meta Game coordination. Word of God says that the creator didn't anticipate this but still finds it immensely entertaining.
Good Bad Bugs: A very common one, in the form of (example): "'This raises an interesting issue,' says Elizabeth Winters, your brother."
Ass Pull: Surprisingly fitting trope to start with. The amount of these that go on within the forum's roleplays could easily fill several volumes, as many nations create implausible characters, technology and even geography- among many other implausible elements in their nation- all in the interest of creating what they believe is a formidable foe within the RP battlefield.
Gameplay Derailment: As a result of the frequent AssPulls, Utopias and "Stop Having Fun" Guys, roleplaying can get frustrating very quickly. The experience can get really deflating if you're a storyteller roleplaying against another nation who wants to show off their (mostly implausible) "super army".
Memetic Badass: Some of the older and more respected roleplayers are this.
On the General (ie off-topic) forum, Lunatic Goofballs has been practically deified. The mods responded by making him a mod.
"Stop Having Fun" Guys: A recurring issue over just about every kind of role playing you can imagine, but most often seen from players who yell at people using Rule of Cool things or invoking the Rule of Drama.
Utopia: The vast majority of the nations on the forum are self-sustaining, resource-rich nations with seemingly limitless wealth, state-of-the-art technology and very few problems, with the utopias often reaching ridiculously unrealistic levels.
Regarding Forum 7, the casual off-topic place:
Memetic Molester: Grittonia, but he is loved all the more for it.
"REGIONS WILL FALL"