There's no such thing as useless thread. The problem is those who think they're smarter, but not experienced (in both internet and modeling) to realize the fact that they can always direct such a thread into a meaningful one. That's when a thread turns useless. Keep in mind that any idiot can call for an FAQ, and such a post is no more than a garbage.
The industry is changing constantly, so are the technique and products, and that means even if a particular question sounds familiar to a few regular people, there's always an option to make the thread meaningful by injecting new ideas and giving fresh information. That can never be done by the novice, which means it's one of the responsibilities of the experienced modelers. Also, we always see new people joining in, and they might know something we, the frequents, don't. FAQ is convenient, and ours is definitely more useful and informative than the others, but it's important to know that FAQ has a risk of restricting people's ability to seek out new ideas.
If you find a familiar-sounding title, just skip it. No one's forcing you to open and read it, let alone adding useless replies.