Andrew, to me, this was never just a home made project group, it had lots of threads about adaptations of available gear, or restorations of old equipment, shop construction and modification, etc. In fact it was nice and open that way, which I liked and continue to like. It was a bunch of mad modders,
And likewise I think YouTube has a place. But it is rapidly re-placing fora. And that is by intention. If a link appears to a forum in a Youtube description (quite rare) and you clicked on it you used to get a warning message that you were leaving YouTube! Did you really want to do that! Gosh........Well why the heck not???
And YouTube goes to great lengths to prevent downloading videos, though it solicits them itself for free. And autoplay is by default checked on. The intention is to keep the viewer locked into the site at all times.
And likewise many YouTube content providers visit a discussion forum merely to post links to their videos or channels to boost their popularity and subscription numbers. They also aim to create multiple links within the forum, one per video, to raise search engine hit counts for their channel.
Frequently they post no actual project discussion on the forum, no photos or drawings or other information that would add separate or unique value to the forum or create discussion. And in some cases, they don't even participate in the discussion of projects by other forum members. They also don't link to the fora on YouTube itself, though they use the fora to increase their own link numbers.
Okay, this may not be conscious exploitation on their part, for a few people, they are just doing what they see others doing. But the effect is the same. Interest leaves a forum, and centers in YouTube, and the forum dies.
To me, there's no problem with occasional links to YouTube videos -- I post them once in awhile myself. And a link to your own channel, if you have one, seems reasonable and understandable. But this isn't a video billboard, it's a forum. I think posting your own discussion content and participating with others in a community is the real reason for belonging to a forum. Fora will dry up and disappear without that. They will not survive if their threads consist of only one-line notes linking to videos elsewhere.
When a forum dies, video links die with it. Loss of a forum is a major loss to the world of personal knowledge. Countless thousands of hours of projects photos and discussions disappear overnight. I think it's important for people to assess their own participation in any forum they like, and do what they can to make it viable.