According to the United States Census Bureau, about 3/4 of all U.S. business firms have no payroll. Most are self-employed persons operating unincorporated businesses, and may or may not be the owner's principal source of income.
So small businesses are definitely the backbone of America. About 60% ~ 80% of all new jobs created can be attributed to small businesses.
For folks like me who are interested in starting up a small business and wanting to participate in discussions for business issues, here is a list of websites that I've found useful.
Reddit r/smallbusiness Forum
Reddit has several free business forums such as r/entrepreneur and r/startup. The r/smallbusiness subreddit has over 570,000 members.
Webmaster Forum
These days, you don't have a business if you don't have a website. So being a website owner, this is a forum to pay attention to and social.
Small Business Computing & E-Commerce Forums
The Small Business Computing & E-Commerce Forums helps its members to “make smart technology decisions.” Users engage in discussions on topics like solving technical issues on websites and handling online security, ecommerce and search engine optimization.
Web Hosting Talk
Discussions on finding a good web hosting for your website.
BizWarriors Forum
Offers a broad array of general business advice. It also features an active accounting and finance forum.
StartupNation Community Business Forums
The StartupNation Community discusses everything about running a small business — from the basics of launching a company to qualifying for a loan to eCommerce efforts. In addition to the general business forum topics, the community offers boards that cover success stories, inspiration and wellness.
Warrior Forum
Warrior Forum’s focus is mainly on Internet marketing.
The Fastlane Entrepreneur Forum
Started by MJ DeMarco, the author of "Millionaire Fastlane". This is an entrepreneur forum where users share business ideas, success stories and setbacks as well as off-topic lifestyle discussions.
Business Advice Forum
A general business forum that discusses various topics relating to running a business.
QuickBooks Online Business Community
A niche message board compared to other small business forums online. If you use Intuit’s QuickBooks as the accounting software for your small business, you can ask questions about the program or accounting issues that arise.
Quora
A question and answer site that has a lot of business related topics.
Medium.com
Although not a forum, but the comment section of each blog post serves as a kind of feedback. So commenting is similar to a forum discussion.
I will keep this updated when I find more websites.