And what people burn out on is that a lot of these collabs go poorly because of artistic differences, or one people being not serious (for good or bad reasons). So if the collab is off-site, that eliminates the completion rate you have on a platform like skeb. IMF solves this by being more a community and so you get to know people more before working with them.
So I'm not sure it is solving really anything, and the approach does not seem sustainable (one email per new track per user? how long before everything goes to spam). But I'd love to be convinced otherwise :-)