Much of the coverage of deflation seems to miss the key point. Deflation is a sign that resources are being wasted. The lower inflation is, other things being equal, the more resources are being wasted. Wasted resources are probably a bit economics speak. What it means is that society as a whole - you and I - are worse off for no reason. There are also good grounds for thinking the sums involved could be very large, dwarfing the numbers the media normally frets about. 
Once you look at it this way, lots of rather silly debates become clear. First and most obviously, there is nothing magic about the number zero. Other things being equal, zero inflation suggests more resources are being wasted than if inflation is 1%, but resources are still being wasted when inflation is 1% and the target is 2%.
Economists have worried about some of the knock on effects that deflation might have. In particular, because deflation means that the real value of debts fixed in nominal terms is rising, that may induce debtors to cut back spending, with no matching increase in spending by creditors. This will make the waste of resources worse. However this effect is not a non-linear one that kicks in when inflation is zero. If this effect is important, debtors will still be more inhibited by their debt if inflation is 1% compared to 2%. And, of course, even if this effect is unimportant resources are still being wasted if inflation is below target.
This is also why looking at some measure of core inflation is important. If below target inflation is just due to lower oil prices, say, which in turn are just lower because of increased supply, say,  then this is no reason to think resources are being wasted. Just as inflation targeting central banks should largely see through any inflation caused by higher oil prices, they should also do the opposite. However in the UK, US and Eurozone core inflation is significantly below target, suggesting resources are being wasted everywhere.
The really interesting thing about the current situation is that in all three places nominal wages seem to be going nowhere fast. This could be partly because plenty of domestic spare capacity exists, but partly also because workers are aware of the potential employers have to use overseas labour as an alternative. In either case, the really good news that this implies is that we can allow the economy to grow at an above average rate for some time. (It also suggests that current fiscal projections may be too pessimistic.)
This is only good news if we take the opportunity it presents. We should use the monetary and fiscal tools we have at our disposal (and invent some new ones if need be) to do so. There is no magic to raising demand - we have various tried and tested means of doing so. The basic barrier to raising demand has been and always will be inflation, so when that barrier is nowhere in sight (in fact appears to be moving further away) it is a criminal waste not to expand demand.
But what of those who advocate caution. We should raise interest rates now, so as to avoid rapid increases later? I am sure some people who argue this way are genuine, but just wrong because they have not realised the implications of the position we are now in, and in particular the balance of risks involved. But I cannot also help noticing that some on the right have been arguing for higher interest rates for some time, and refuse to admit they were wrong. They are confirming Kalecki’s idea that although what he called full employment was good for society, it may not be good for some particular parts of society. Those pursuing this line should not be dismissed: they should be laughed into obscurity.
 This would be clearer if all central banks had a dual mandate.
 Which in the current situation is probably not true, so this is just to make the point.