China is an extraordinarily difficult market to crack for outsiders. It's dominated by domestic companies across nearly every product category / industry.
For Amazon I actually think this move makes sense. If you can't beat 'em, join 'em. There's no reason Amazon can't build a ~$40 billion per year type business riding on another platform in the massive China market (say over the next decade). Alibaba makes all of its money from advertising, and essentially zip from product sales. Amazon makes almost all of its money from product sales, and almost zip from advertising - Tmall is a great way for Amazon to drive sales via riding Alibaba's platform.
For Amazon I actually think this move makes sense. If you can't beat 'em, join 'em. There's no reason Amazon can't build a ~$40 billion per year type business riding on another platform in the massive China market (say over the next decade). Alibaba makes all of its money from advertising, and essentially zip from product sales. Amazon makes almost all of its money from product sales, and almost zip from advertising - Tmall is a great way for Amazon to drive sales via riding Alibaba's platform.