Check out the official r/Shopify community on Reddit, where Shopify merchants, developers, and partners from the ecosystem come together and help one another.
EcomHub's official Facebook group is for high-level discussions and all things Amazon FBA & eCommerce strategies.
This group by Justin Cener is a general purpose ecommerce group with over 50,000 members where you can learn about dropshipping, influencer marketing, and using FB ads to build an online business.
This is a free community for Facebook marketers, freelancers and agency owners. With over 100,000 members, the group is run and moderated by Digital Distillery & Cat Howell.
Alex Fedotoff runs a Facebook group with nearly 50,000 members dedicated to intermediate-advanced Facebook advertisers and eCommerce entrepreneurs, who are spending $5,000 - $1,000,000+ per month on ads. If that's you, this might be the right place to pose problems and learn from marketers.
r/ecommerce is a subreddit for anyone interested in the operations of ecommerce websites. Ask questions, have honest and helpful discussions on marketing, seo, products, checkout, conversions, etc.