For those of us who are not sure what BitcoinDays Destroy means... what is the value of knowing these numbers?
Basically, the system is currently creating about 6.3 Million Bitcoin days every day. In layman's terms, that means that each day that goes by, the 6.3 Million bitcoins could have been hoarded for another day. If a hoarder cashes in some of their "stash", then they "destroy" Bitcoin Days. Destruction of BitCoin Days is a healthy thing. It is a measure of circulation.
To date, there have been approximately 27.3 Billion Bitcoin days created. And about 2.2% of those have been destroyed. This figure has been rising steadily. (See my post that I linked to, above). Since this is RISING, this means that more and more bitcoins are being circulated - a very good thing for the future prospects of Bitcoins.
If you are a speculator, you'd be wise to keep an eye on that "cumulative Bitcoin Days Destroyed" figure. If it begins going down, that means that less bitcoins are being circulated, and more are being hoarded. That's the sign of a bubble forming. (This may be hard to believe, but we're not in a bubble now - the cumulative bitcoin days destroyed is increasing, meaning there's more spending and less hoarding than there has been in the past! This is a VERY good sign for the long-term viability of Bitcoins.)
If cumulative Bitcoin Days Destroyed begins to go down, that's an indication that people are "over-hoarding".