Is google planing to fight against google toolbar hackers?
Google has changed the Toolbar Checksum algorithm (it is not the first time, but there are not much updates). During a transition period, both algorithm are valid (if you still have an old version of the toolbar, you still can see PageRank) but in the future Google may only allow the new algorithm. If it's the case, all the tools based on the cracked version of the toolbar checksum algorithm won't work anymore...
Learn more about this by reading this blog article: Google changed the toolbar checksum algorithm