What is happening in Ascomycete classification

Ascomycete taxonomy has changed in the last five years, and the change has been rapid. New classifications have been proposed and rejected. There has been a flurry of meetings, and familiar groups like the Discomycetes have been set aside as 'artificial'. Many mycologists, including taxonomists, have found this bewildering. Which classification should they follow? What, if anything, has replaced these supposedly outmoded groups? What are the main changes, and why have they occurred? In this personal view, I try to provide some of the answers.