Most courses at my institution are now administered with Canvas, an integrated online service, so there is little need for any outside course webpages. Still, I’ve left up a few pages for older courses when there could be information, such as old exams or lecture notes, that future students could find valuable.
I have allowed my “Teaching Blog,” an experiment undertaken while teaching a semester of Math 170, to remain up….. in part as a warning to others. The experiment, not altogether successful, was meant to encourage students to engage with the mathematical material in a novel way, and to contextualize mathematical developments both historically and through the human personalities responsible for making them. Unfortunately the students rather ignored it, and would comment only when some form of coercion was applied (making it part of an assignment, say). I’ve noticed all student comments have been removed, likely because the students themselves have left University and had their University-sponsored online presence has been terminated.