what is the key source of revenue of Alibaba?

Alibaba's China Commerce business, where revenues are derived from retail e-commerce and associated marketing services in China, is expected to contribute $49 billion to Alibaba's fiscal 2020 revenues, making up 65% of Alibaba's $75 billion in revenues for fiscal 2020.

The China Wholesale and Other Revenue are expected to be about 12% of total revenues, where wholesale commerce and logistics service revenues are primarily driven by Chinese consumption.

Alibaba's China Commerce business will provide $32 billion, that is 62% of $52 billion in total revenue the company is expected to add between fiscal 2017 to 2020.

This China Commerce growth has been key to Alibaba's 145% price appreciation during the same period, further helped by stable margins, and strong expansion in Alibaba's valuation multiple.
Alibaba's revenue grew 144% over 2017-2019 to $56 billion and is expected to increase by 78% to nearly $100 billion by 2021.

Expectations for Alibaba's revenue drivers are:

1)China Commerce Division Revenue growth of about $5 billion over the next two years will be driven by the growing need for digital transformation among brick and mortar stores in the world's largest country by population.

2)China Wholesale & Other Division Revenues to grow by about $4 billion over the next two years due to an increase in logistics and wholesale business.

3) Cloud Computing Division Revenues to grow by about $5 billion over the next two years due to an increase in average revenue per customer, wider partnerships, and Alibaba's launch of newer cloud products.

4) Alibaba's recently-launched SAAS accelerator helps deploy cloud-native technologies across customer IT environments to speed up the adoption of Alibaba's cloud.

5) Digital Media & Innovation Initiatives Division Revenues to grow by about $2.7 billion over the next two years due to increasing in local language content consumption.

Over the next 2 years, we expect these segment revenue to increase by $2.7 billion - likely driven by continued growth in local language content consumption.