Shopify + Woocommerce power over 50% of top 1M ecommerce sites
Ecommerce platforms are dominated by Shopify and WooCommerce. Together, they power 52% of the top 1 million sites, according to current stats from BuiltWith. Woocommerce leads with 29% and Shopify power 23% of the top ecommerce sites.
The two platforms are quite different from an operational standpoint. WooCommerce runs on the open source Wordpress backend. Wordpress sites can be hosted by Automattic, the company behind Wordpress as well as self-hosted, i.e. hosted by third-parties. Shopify is entirely a hosted cart, with Shopify maintaining a degree of control of the backend code.
Shopify has received a lot of attention lately, at least in part due to the rampant run of its stock price since the IPO. The company is known for helping the "army of rebels" that makes up independent businesses fighting back against the large retail companies. Interestingly, it's WooCommerce that is perhaps better suited to make this claim, by truly giving merchants the tools they need and the ability to use on their own terms.
The strength of Shopify comes from the fact that it is a hosted cart. There are continual improvements, themes and apps work well, and stores stay updated with new features. There's a price to pay and it's incredibly small for the set of tools provided.
The number of sites powered by Shopify and WooCommerce is somewhat less important than market share of meaningful sits. These two dominate now, and represent two different methodologies of free & open-source vs paid & hosted. I predict Shopify will come to win a larger share of top sites and will check back on that prediction in time.