Yahoo Answers are not just answers user's post to questions on Yahoo. Yahoo! Answers is a specific type of trolling in which a stupid question gets asked, followed up by an even stupider answer, by different people and with no coordination between the two.
Pacman looking chart showing the primary purposes for Yahoo Answers. claiming most of it ends up on Failblog.
The truth is strong with this one. The dynamics of Yahoo Answers in which it basically invites trolls to get a place for some attention makes it more entertaining than reliable for good answers. So yeah, naturally a bunch of it will reach fail blog, cause that is where that goes. Yahoo! has known about the issues for years but it still generates traffic for them, which is better than no traffic, and also it still does have good answers to some basic questions that made it through the system over time. That alone give Yahoo Answers a reason to keep it going and pump out content for Failblog enthusiast without a concern of running out of supply.