Just shy of 2000 different licenses cover the 230,000+ projects in the Black Duck Knowledgebase. It's important to note that the top 10 licenses cover 93% of all projects and the top 20 almost 97%. Well over 60% are GPL. So, the vast bulk of projects are under a small number of well-known licenses, and that's a good thing. But the other 3% of projects and 1980-odd licenses (and there are some odd ones!) clearly constitute a "long tail." Join me, won't you, for a journey to the outer reaches of that tail.