Mikes Protocol, also called the Shareaza protocol or Gnutella2 (by the developer, which created much aversion against it by other developers), abolished backwards compatibility for some performance perks and independence from the_gdf. It is incompatible to Gnutella but follows similar principles. shareaza still connects to the Gnutella Network and can transfer results from one network to the other (when the user enables this) It can download from Gnutella and Gnutella Clients can download from Shareaza, but only, when the Shareaza User enables this.
There have been several claims, that Shareaza harms Gnutella by several meeans, but so far no clear action followed those. Naturally they could also be misinterpretations based by built up aversions.
Shareaza itself looks promising, and the author of this text sees it as a big step forward, that they recently stopped calling Gnutella "gnutella1" on their page. Maybe its competition will also be good for other programs, to make them adopt necessary changes, and that will make Gnutella more efficient in the long run.