With wet blending both colors are placed on the surface, still wet, and then mixed together. With feathering the under layer is already dery and you are placing a lighter color on top and \"drawing\" out the paint until it fades into the darker color.
To add on to the feather article, using a drying retardant will help with ease of feathering since you will not be a rushed to wipe your brush, redampen it, and pull the wet paint. The retardant gives to a bit of time to work with the paint to get it just right. I learned this from the Hot Lead painting DVD.