Advasense made quite a lot of noise with its impressive 1.4um pixel announcement a few days ago. The company has few presentations on its web site. One of them, "The Small Pixel Race" from over a year ago, compares Advasense feedback pixel with 4T pixel:
The presentation also tells a little bit about image stabilization feature: "A series of short exposed images are captured, aligned and summed up in the same pixel array. Pixel array is used as memory during the stabilization process"