I also found the examples confusing. What I got is they are all nouns (respect the grammar rule of having nouns for class names) but `PlanEvents` reads like data that is going to be processed (passive) whereas `EventPlanner` and `Scheduler` are concepts that process data (active). They have a verb: "plan" and "schedule".
Thanks for clarification. I think I disagree with the author here. In my experiences, it's sometimes awkward to use '-er,' '-or' suffixes to turn name into concepts that process data (active) e.g. JobUpserter, ...
