I know, I'm not supposed to talk about "Forge" topics without an awful lot of details and mandatory caution, but I won't. I simply don't have the time/energy anymore to go into such extend of gaming theory, especially since it sucks a little bit of the very same energy I use to write and to play. This post is thus bound to fail Forge-wise but still, I'd like to point at a few things in it.
You know, the Big GNS Model and its implied truths: games are different because they address different Creative Agendas, they should be tuned to a specific agenda, Color and Setting instead of the fantasy heartbreakers/kitchen sinks they've become, their system, which matters, should have teeth, and the like.
In my own experience, going through The Forge and participating there was key in bringing me back to the Old-School systems through Matt Finch's Quick Primer for Old-School Gaming and I've come to consider whatever I did on The Forge as a pre-OSR training of sorts.
Yet, when we look at what the OSR is, it turns all The Forge principles head over heels: specific Creative Agenda? No way. Fantasy heartbreakers are bad? No, they're awesome. System Matters? Hell, yes, but not like you think. Having teeth, resolution mechanics implying a specific way of playing, deeply embedded into the system's mechanics? Of course not, these games are about freedom, goodbye Luke Crane. Strong theory backing our designs? We have the Quick Primer, thank you.
Oddly, it's the OSR that manages to fulfill all what The Forge somewhat failed to accomplish in its days of glory: punk venues, open source, PDF & POD, internet coverage, conventions, a hell of a buzz, reaching everyone, mature gaming, ashcans everywhere, etc. I could say that The Forge is actually an ancestor of the OSR. I could.