While not specifically about ecommerce, r/smallbusiness is a great place to ask questions and learn from others who are starting, owning and growing a small business.
Gabriel St-Germain's private Facebook group for people who are learning about e-commerce, FB ads, IG influencers, and everything in between.
Join the official Slack community for Shopify Partners such as app developers, theme developers, Shopify agencies and other ecosystem partners who work towards enabling merchants. It's a large and active community of people all across the world, and is also the official channel for Shopify Partner Townhalls.
From the creators of online business podcast Silent Sales Machine Radio, join this group with over 60,000 members and learn how to sell on Amazon or eBay marketplaces and grow your ecommerce business.
VerumEcom focuses on providing high-quality training and resources for people looking to either start their first e-commerce business or take their existing business to the next level.
Run by Steve Tan, this Ecommerce Facebook group is super active and busy with over 100,000 members. Discuss genera eCommerce, Shopify/Magento tips, Facebook Ads, Social Media Marketing, information about Product Sourcing, Fulfillment, Traffic and Conversion.