I would say the difference is that forums are about topics/discussion while social media is about people.
There is a difference if you use it to discuss your interests with like minded individuals or if you broadcast to an audience.
I think this is why social media mostly works in small groups or why many people on facebook still find groups with limited topics useful even if they hate the rest.
It is also my main gripe with things like SSB or the fediverse. They work much better than other social media, because they encourage smaller, more tight knight communities, but they are often still people focused, not discussion focused.
There is a difference if you use it to discuss your interests with like minded individuals or if you broadcast to an audience. I think this is why social media mostly works in small groups or why many people on facebook still find groups with limited topics useful even if they hate the rest.
It is also my main gripe with things like SSB or the fediverse. They work much better than other social media, because they encourage smaller, more tight knight communities, but they are often still people focused, not discussion focused.