I think AvE is an awesome channel! I really appreciate the hacker attitude combined with genuine mechanical knowledge and experience. And also extremely funny!
But as for the forum question -- I'm vaguely concerned about whether this forum software is up to the task at the moment. I mean, using AvE forum as an example:
-- Being able to see AvE forum posts at the same time as EEVBlog forum posts is essential for AvE forum to reach any kind of critical mass. If I have to specially visit the AvE forum on a separate site, and there isn't much life there, I'll pretty quickly stop checking there and it'll just fizzle out. Not to mention the first-time registration inconvenience.
-- However, as mentioned by others, the "unread messages" section would just become a jumble of EEVBlog, AvE, w2aew, signal path, etc etc posts, and so in that sense it becomes an everything forum where you're automatically subscribed to everything, which understandably is not what everyone wants. (Though I personally am OK with it, the lists of bloggers in this thread are basically my subscription list in YouTube, I fully appreciate that other people have different tastes).
This is a software problem -- I know the site admins/Dave may hate me for suggesting this, but if there's some kind of feature/mod whereby you can choose that "unread messages" respects a whitelist or blacklist of forum sections, then each individual user gets to choose whether the forum stays pure EEVBlog from their perspective, whether they want an all inclusive jumble of everythingness, or indeed, if they decide that they love EEVBlog and blog X but hate blog Y, they can have their dream forum too. That way, everyone's happy.