My erstwhile friend Tom Clark of the Guardian offers - like a vastly more erudite Jason Donovan - 10 good reasons why Yes lost. I won't duplicate that here because it's a fantastic analysis and I've covered a lot of similar ground in previous posts anyway. Instead I'll offer some thoughts on why AV was the wrong question to ask - and where future efforts at voting reform might go from here.
AV is a piece-of-cack voting system, really, mainly because it's too similar to First Past the Post to get far enough away from the huge problems with that system. Most obviously, it's not proportional. As the main (and justified) complaint of the Lib Dems (and before them, the Alliance, and before them, the Liberal Party) about the British electoral system was that it was not proportional, it's a bit odd that they settled on a referendum on a system that didn't address their main complaint. "Ah", the Lib Dems will tell you, "but the Tories weren't offering that." Fine - they should have said "no deal" then. And then allowed the Tories to go ahead with a minority govt. They would be in a far, far better place now had they done that. It would have been the Tories, not the Lib Dems, who lost 700 local council seats today.
In the event, the main pragmatic argument from the Lib Dems for voting yes to AV was that it was a stepping stone to further reform later on. But that would imply that AV was a more proportional system than FPTP - and there is no strong evidence for that. So therefore, the 'stepping stone' argument was always shaky. As was the argument for voting yes on its own terms. It was a fuzzy, confused campaign, for a "miserable compromise", neither-this-nor-that voting system. And that, coupled with the inept way the campaign was put across and the uniquely catastrophic contribution of Nick Clegg, did for it.
So what next for electoral reform? Unless we get a freak result where a shrunken Lib Dem party can nonetheless hold the balance at the next general election, it's going to be a long while before they're in a position to demand a PR referendum - and even less likely that anyone will agree to it. So it's down to the other smaller parties in that case - particularly the Greens and UKIP. And if we're looking to those guys to hold the balance of power in a hung parliament - it's gonna take a while to happen. Current MP totals: Greens - 1, UKIP - zero. The best chance for PR is that one party becomes so dominant (the Tories for example) that there is an 'anyone-but-Tory' electoral pact across hundreds of constituencies to vote in MPs who will legislate for a PR system, followed by fresh elections. Possible... but hard to pull off.
But if this wretched referendum has had any value, it's the way the "Fib Dems" have become a salutary lesson to any third party that thinks it can sell out principles for quick power, and play fast and lose with its voters. Any third force emerging in the future - and I think the Greens are most likely - will have to act with much more principle than the Fib Dems to be taken seriously. And that, in the end, is a good thing.