A new version of Goombah is available. It addresses a number of issues including compatibility with Tiger. Probably the most significant change from the users' viewpoint is that the control to set the number of neighbors used for making recommendations is now front-and-center beneath the recommendation list.
This helps you tune recommendations in helpful ways. For instance, suppose you have kids and have a few kid's songs in your collection, but mostly have grown-up music. If the number of neighbors is high, you may get some neighbors who have a lot of kid's music that closely matches yours. Then you may get recommendations for kid's music. And you may or may not want that. If you don't, you can lower the number of neighbors, and this will cause Goombah to base its recommendations on those individuals who have the broadest-based similarity with you, and the kid's music would thus be likely to disappear from your recommendations list.