The rise and fall (OK — mostly fall) of Yahoo
Quincy Larson

A good summary, but accusing them of selling Alibaba too early isn’t quite fair (although symptomatic of their failure to innovate you rightly highlight). Yahoo were under intense pressure to divest by Alibaba themselves. 
Alibaba originally saw them as a strategic investor with expertise they could take advantage of, but quickly realised they were dead weight.
This was before they were public in HK — at one point there were rumours that Alibaba would ring fence Yahoo’s equity from the high growth areas of Alibaba’s business, Yahoo had to divest to appease them. Yahoo did well to hang onto such a large share of Alibaba as long as they have.