The 'answers' on this site often come from the average Joe (or Joanne) on the street, which is often not a very trustworthy source in my opinion.
On the upside, many questions I have about something have already been asked and answered, which is useful I often get just enough useful information to steer me in the right direction to learn more, if I need to. And some users will provide links to validate their answers, which is good.
On the other hand, this is also a place of mischief, and children might not know how to differentiate from the wise answers and the foolish ones. Parents, I recommend having many conversations with your children that will help them to exercise good judgement. Their world will be one of abundant information. They will need to know how to sort it for themselves.
Sometimes, answers are insightful and useful. More often, though, the information on Yahoo Answers is simply moronic. It's usually ideologically motivated misinformation or incomplete/incorrect information from well-meaning but uninformed people. Unless you already have some understanding of the answer, it can be hard to tell whether a given well-voted answer is a good one or a bad one.
Yahoo Answers is one of the most useless information websites. A bunch of people who just like to give their opinion but their knowledge is very limited. Therefore the answers will often be confusing, wrong or incomplete and one-sided. The more expert and underpinning knowledge is required to give a proper answer the more useless Yahoo Answers will be.
Y!A is not for children. TOS state no one under 13. I have seen avatars that show images of explicit sex. I have seen links added to answers that will take a person to sexually explicit videos, but the link was misrepresented as an answer to something else. There is a high risk of insulting content that Y!A can not filter b/c "trolls" no how to bypass those filters. To be safe, when an answer sounds good, search for the recommended advice given before trying it out personally. Some tips sound good but are actually harmful. I was given a camping tip to prevent insects from entering my tent. Had I not checked the product on line, I would not have known that it reacts badly when exposed to water. This means, I would have harmed my tent & body if I used the product during a rain. Use common sense when using this site. It's helpful, but has a lot of tricksters too.