I've been trying to bring attention to this project for years. It directly addresses the whole "proof of work is proof of waste" problem. Some of my earliest submissions to HN were about GridCoin, and they largely went compeletely ignored, glad to finally see it on the front page. At least with BOINC you end up with something more worthwhile than just bruteforcing hashes.
What happens if you have a coin based on "useful work" and you "solve" the problem you were hoping to solve. Now a lot of "miners" leave the network, presumably because they were only there to help solve that particular problem. Now you have a weak system, and a system subject to 51% attacks by adversarial miners, and therefore not a good money/coin.
I don't see how HN commenters (in large part) don't get this. It's the Single-responsibility Principle, just in a different context.