His main contribution, at least in the terms Gingrich and the right talk about, is that he was all about destroying his "enemies". Alinsky used the word "enemy" to describe almost everyone who wasn't a lefty. He also in practice believed that since conservative, business, and the right were his enemies, the ends justified the means. From his book:
The eleventh rule is: If you push a negative hard and deep enough it will break through into its counterside. … The thirteenth rule: Pick the target, freeze it, personalize it, and polarize it. (P.126 -129B)
Didn’t Hillary Clinton write her college thesis on Alinsky?