alt Hacker NewsPEM actually gets used? People depend on it? It hasn't been a market success, but if the root keys for DNSSEC ended up on Pastebin this evening, almost nobody would need to be paged, and you can't say that about PEM.
Multicast gets used (I think unwisely) in campus/datacenter scenarios. Interdomain multicast was a total failure, but interdomain multicast is more recent than DNSSEC.
HIP is mid-aughts, isn't it?
Fair enough on Multicast and HIP. I'm less sure about the case for PEM.
S-HTTP was a bigger failure in absolute terms (I should know!) but it was eventually published as Experimental and the IETF never really pushed it, so I don't think you could argue it was a bigger failure overall.