Download this Dataset of 12,118 Yahoo Answers for $1
blog.diffbot.com> we scraped it all (at least as many as we could find on their English site) 12,118 questions
There's a lot more questions on Yahoo Answers. Their robots.txt file contains a sitemap: https://answers.yahoo.com/sitemaps/sitemap-us.xml
That sitemap contains links to 2,115 other sitemaps. Each of those sitemaps contains links to around 47k questions.
Good find! Worth a follow up to get more!