Huh, I when I looked at my realm in RW to answer how I do it, I realized that I'm all over the place.
If it is a game that the party may play, I'll have a mechanics article. For example, EN World had an article on archery contests that I liked, so I summarized it in a "General Gameplay Article" but I have mechanics for "racing" as part of a an article on chases, which is entered as a General Game Mastering Article.
For flavor text, I'll mention popular games and entertainments as part of an applicable Group:Ethnic article. For one game that was part of a more involved series of adventures, I entered it as a 'further information' topic, as it was providing further information on an aspect of culture for a specific ethnic group.
So, I am not very consistent, but I've become less OCD in my use of RW over the past two years and I just let it grow organically. Where does it make sense for me NOW in terms of helping me prep for my game? Autolinking and the ease of moving items to different container and even changing a topic from one topic to another makes me comfortable that I'm not going to lose or break anything.
I find that how I want to "file" things in RW changes over the course of the campaign. I organized things for an upcoming advanture to make it easy to work on and to run the game. Afterwards, its purpose is more to be part of the world almanac and the players interactions with the concept, group, etc. leads me to expand upon it, so it gets moved, become its own topic or a different topic.
The only thing I don't do is convert topics to articles and vice versa. I'm pretty clear that mechanics articles are for crunch and almanac/view topics are for fluff. I *could* do so, you can find posts in the forums where Rob will step you through it, but it is a bit involved. I think spending sometime on understanding what you'll put in the mechanics section and what you'll put in the almanac section is worth it, beyond that though, I don't sweat it.