I'm thinking generally about electronics, because I like tech stuff, but I don't see a reason to limit it to just that category. The idea of a federated review system is kind of what I'm getting at, with the posibility of encompassing things like design, collaboration, speculation for ways to improve, (repairability would be a great thing to cover as well, but I'm not extrememly savvy when it comes to repair!)
I think that a federated library of product reviews/discussions could be a great resource.