Thanks for your comment. I found more context about the teacher profiled in the Mashable article in this older article from an Education Week blog:
http://blogs.edweek.org/teachers/teaching_now/2011/09/teache...
My initial surprise at the announcement that lesson plans sell that well stems from
1) writing my own lesson plans, adapted to a particular group of students I teach, and thus
2) thinking, don't most teachers plan their lessons for their particular class, with its individual mix of students?
while also knowing
3) many materials provided by textbook publishers have somewhat of built-in lesson plans.
So I'm still surprised to see that the market is as large as it evidently is for canned lesson plans, but it is, and it appears that other teachers ought to enter it.