When you purchase from Disney, you will always get the points in the current Use Year and then again when your Use Year begins the next year - for example - if you purchased today from
DVC directly with a March Use Year- you would get your points (the current minimum purchase thru Disney is 160) from the current Use Year and then another 160 points on March 1, 2010 and again on March 1, 2011 , etc.
If you purchase 100 points via resale, you would get whatever points are available in the contract and then whatever points are available from the next Use Year. As an example - if you purchase a contract of 100 points with a March Use Year - it's possible to have banked points from 2008, all current points from 2009 and all points from the 2010 Use Year for a total of 300 points available - BUT - it's also possible that the contract would have no banked points from 2008, no points from the current 2009 Use Year and some or all of the 2010 points could already have been used - leaving few or no points available until March, 2011. (That is referred to as a "stripped" contract.) That status would be known before purchase - so be sure to that into consideration when buying a resale contract.
Most resale contracts fall somewhere between "all banked points, all current points and all future points" and "no banked points, no current points and no future points in the next Use Year" - while purchases from Disney will
always have all current points and all points from the next Use Year. In some instances DVC has also offered Developer Points as an incentive - but that is not presently the offer.