If you're new to the ecommerce game and just about to make the plunge, Shopify Newbies is a strong group with close to 100,000 members that can help you get started on your Shopify ecommerce business journey.
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.
Join the 7 Figure Ecommerce Secrets Group to learn from Rafael, who manages this group of 20,000 Shopify and dropshipping entrepreneurs trying to grow their business with Facebook Ads and Instagram influencers.
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.
A collaboration-focused Slack community of Shopify and Shopify Plus partners. This invite-only community has almost every significant person from the Shopify partners community. If invited, the group charges a $149 quarterly fee.
Richard Lazazzera of A Better Lemonade Stand runs Ecommerce Entrepreneurs. With close to 50,000 members, the Facebook group is one of the largest forums for discussion, learning, and growth on Shopify, ecommerce, digital marketing, Adwords, SEO, SEM, web analytics, content, CRM, etc.