Yahoo are the last of the major tech companies without an intelligent virtual assistant, so this isn’t really a surprise, especially as search is moving to natural language input. This quote points to them concentrating on natural language understanding:
there’s a really interesting place to play there, to help people make better sense of the content they already have access to
It will be interesting to see how they handle the fact they don’t control a hardware platform nor a browser – speech input may be difficult on non-mobile platforms.