What happened to the world perks points now northwest is under Delta Airlines?
Delta finished the merger of the Northwest Worldperks FFP into its existing Skymiles FFP on October 1, 2009. At that time, one of three things happened. Users with a Worldperks account but no Skymiles account had only a Skymiles account going forward. Users having both who had previously responed to the request to link them had their Worldperks account merged into their Skymiles account. Users with both accounts that didn't link them ended up with two Skymiles accounts and had to merge them manually.
The miles were merged. So as an example if one had 20000 miles under Delta and 50000 under Northwest the total became 70000. In addition 1500 bonus miles were given to everyone who merged.