I kind of thought "tacking" was using some sort of stitching - like "turkey tracks" - to hold the layers together.
Here are some links to "turkey tracks" or "crows feet" or "lazy daisy"
http://www.quiltingboard.com/t-1753-1.htm
http://www.quiltingboard.com/t-19582-1.htm
http://www.quiltingboard.com/t-26051-1.htm