I've seen a few of these lately, and I'd like to speak against them.
Placeholder topics should simply not be allowed - a minimum amount of info should be required prior to posting a topic.
Others might have alot of info on the topic and be forced to post into the bare topic and possibly have their post buried.
For example, the first topic about the quiz event quite literally gave no information other than 'it exists'.
Placeholder POSTS should still be allowed, especially when writing large guides and dealing with the character limit.
Alternatively, if a topic is posted that has much more info than a placeholder topic, the placeholder topic should be merged with that new one under no penalty.