For example, we don't need entire threads dedicated to topics such as:
-Justin Beiber's music in your nation. (Or other real-world issues that may have nothing to do with a majority of players here)
-$insert_language_here in your nation. (You can do your own languages in your own factbooks/dispatches.)
-Anime in your nation.
-Squirrels in your nation. (Or any other animals, llama or otherwise.)
-My made-up religion in your nation. (Or splinter group, or special interest organization, or any other of your bits and whether they are outside your nation - take it to RP, or make up a thread here where people can sign up to have your group in their nation - like the embassies.)
And so on. These aren't worldbuilding for player nations, they're little more than spammy word games.
If you want to start a thread in here besides a basic "My Nation's factbook," put some thought into what you are asking about. Is it a topic even worthy of national level policy or attention? Are the likely responses to be one-liner things like "Yes we allow this" or "No we don't?" Also, your opening post sets the tone for the thread. You had better be including your nation's stance on whatever subject it is, and fleshing it out some to encourage subsequent posters to do likewise.
For example:
A crappy FN&I OP:
What disasters happen in your nation?
A slightly better OP on the same exact topic:
What disasters happen in your nation? How does living with them affect your nation's population, and how does the government respond to the danger? Has it affected anything about how your nation works?
And a really good OP, also on the same exact topic:
What types of disasters can or have happened in your nation? Are they purely natural disasters, or are there some that have been caused by wars or other activity? Do people or the government actively prepare to deal with any of them? Does the threat of any of them affect how people behave, or have any been historically significant?
In Nationistan, our most common serious disasters are strong blizzards in the winter months. When most of the nation can look forward to being buried under several feet of snow every year, it's not uncommon for buildings to be built with doors on the second or third floor so that people can still get out if the bottom floor is completely buried. People prepare every year by stockpiling non-perishable foods, and most families will have an emergency generator and heater in case a storm knocks out the power for days at a stretch. The government also has a series of emergency heat shelters in urban centers and along major highways to try and help keep stranded motorists safe, and we probably have one of the largest and most advanced snowplow fleets in the world.
Probably the most historically major one was the Great Blizzard that happened 100 years ago. The capital was buried under several dozen feet of snow when the storm hit while the emperor was holding court and deciding along with his top generals and advisers what to do about a rebellion brewing in the south. The storm was so fierce that he was completely cut off from the outside world for nearly three months. By the time they were able to dig out, the rebellion had captured several key positions and managed to hamstring the emperor's military. Experts claim that the rebellion was ultimately able to succeed thanks to the blizzard stalling the government response, leading to the emperor's downfall and the establishment of the current republic.
The first just encourages spammy one-liner answers. The second at least expands slightly on the question and offers more angles for potential responses. The third expands considerably on the question, and sets the tone for responses by offering up the OP's own answer to the question.
So if you start seeing a bunch of threads being locked, this is probably why.
~Evil Forum Empress Rep Prod the Ninja Mod
~She who wields the Banhammer; master of the mighty moderation no-dachi Kiritateru Teikoku
(Edited by Nathicana 1/31/15: added explanations for better clarity)