Bing is powering Yahoo, Bing/Cortana and Siri. With Windows 10 having baked in Cortana, Bing will a lot more footprint. Bing is the farthest thing from failure, they are making money as of now, the whole sinking money into bing and xbox is really really old news.
That depends on Windows 10 being a huge success, and they are kind of fucking it up. Aside from the interface still apparently missing the point, I don't think a lot of people appreciated the ad/nag showing up in their system tray. I will put off getting W10 for at least a year for that alone.
