Here is what I believe summarizes the restrictions:
Effective for any resale occurring on or after:
March 21, 2011: cannot use points from the resale to reserve the Disney Collections (Disney hotels), Concierge Collections (certain non-Disney hotels a list of which can be found on the DVC member site
https://disneyvacationclub.disney.go.com/destinations/list/concierge/),
Adventures by Disney, or a
Disney cruise.
April 4, 2016: cannot use points from the resale to qualify for any incidental benefits a/k/a membership extras. Exactly what is excluded under the rule has often been the subject of discussion. Things you can still definitely use are RCI, pool hopping, the TOWTL lounge, free parking at the resorts and, if staying on site, free parking at the parks, and the DVC dining plan. Things you cannot get are member dining, recreational, and merchandise discounts; discounted APs (or any other DVC ticket discounts that may be offered at any time); Moonlight Magic or other member exclusive events. Some have mentioned being able to get access to the DVC Epcot lounge, the golf discounts, and able to purchase Tables in Wonderland despite having only resale points purchased after April 4, 2016, but some have reported otherwise so issues remain unclear. If you own no points purchased before April 4, 2016, you can still get access to membership extras if you purchased any points from DVD after April 4, 2016 but before February 25, 2018.
February 25, 2018: you need at least 75 points purchased from DVD to get membership extras unless already entitled to them as result of previous purchases.
January 19, 2019: cannot use points from the resale of any DVC resort that existed before Riviera to reserve Riviera (or likely any other future DVC resort), but the points can be used for those DVC resorts that existed before Riviera. Any resale of Riviera points results in the purchaser being able to reserve only Riviera (resorts coming after Riviera will likely have the same type of resale restriction applicable to the specific resort).
September 17, 2019: You need at least 100 points purchased from DVD to use membership extras unless already entitled to them as a result of prior purchases.