Some of the most popular/used forums are:

1. Stack Overflow:

A popular forum for programmers and developers to ask questions and seek answers related to software development, coding, and technical issues. https://stackoverflow.com/

2. Microsoft Support:

Microsoft Support page: https://answers.microsoft.com/en-us

3. Reddit /r/programming:

A subreddit dedicated to discussions and sharing of programming-related topics, news, and resources. https://www.reddit.com/r/programming/

4. Spiceworks Community:

A platform where IT professionals can connect, ask questions, share knowledge, and discuss various IT-related topics, including hardware, software, networking, and cybersecurity. https://community.spiceworks.com/

5. TechNet Forums:

Microsoft’s official community platform where IT professionals can find support, ask questions, and discuss Microsoft products and technologies. https://social.technet.microsoft.com/Forums/

6. Cisco Community:

A forum for networking professionals to discuss Cisco products, technologies, and solutions, as well as seek guidance and share knowledge. https://community.cisco.com/

7. Tom’s Hardware Forums:

A community-driven platform focused on computer hardware and technology discussions, including troubleshooting, product recommendations, and DIY projects. https://forums.tomshardware.com/

8. TechRepublic Forums:

A forum for IT professionals and enthusiasts to discuss various technology-related topics, including cybersecurity, software, hardware, and IT career advice. https://www.techrepublic.com/forums/

9. Linus Tech Tips Forum:

A community forum associated with the popular Linus Tech Tips YouTube channel, featuring discussions on technology news, hardware reviews, and DIY PC builds. https://linustechtips.com/main/

10. XDA Developers Forum:

A forum dedicated to mobile device development, customization, and modding, covering topics related to Android and other mobile platforms. https://forum.xda-developers.com/

11. WebHostingTalk Forum:

A forum for web hosting professionals and enthusiasts to discuss web hosting, server management, website development, and related topics. https://www.webhostingtalk.com/
Please note that the popularity and relevance of forums can change over time, so it’s always a good idea to explore multiple sources and communities to find the most suitable forum for your specific needs.