I think indogulf & guy betsy has your answer.

There seems to be 2 main types of RTW tickets that I have seen: 1w Explorer, and Global Explorer.

The Global Explorer has been around longer and used to be better than the old RTW tickets before 1w was formed.

Now that they have the 1w Explorer fare, I find this to be better.

At the moment, I cannot remember the specific differences between the two types of RTW. However, it looks like one of the differences are the business class tickets on a 2 class plane!