Hi, I just added a tutorial about the topic. Wordpress The Basics And Most Common Tasks

You have it on the right when you type the post. You create a category yourself or choose among those that you created earlier.

Here's the tutorial for that WordPress Tutorial - Creating Categories

We don't have exact numbers, but I can tell you that it is very low compared to those that are promoting within their own respective niches/interests that they have chosen.

The training sets people in the direction of choosing their own niche and that is the focus of the training.

Many people will decide to promote WA down the road once they have experience, there are others that join the community and simply love the experience here and want to promote it, or there is a select number of folks that simply want to work within the make money/internet/affiliate marketing world.

Definitely a much larger percentage of folks NOT promoting WA versus promoting WA. The reason, there are MILLIONS of niches out there.

Most likely this is impossible to tell. Personal choice in any case.