As someone on the hunt for badges, I am doing my best to offer solutions as I know many of you are. Nothing breaks my heart more than delivering a solution and not getting that "Marked as Solution" tag.
Looking down the list of Discussions in Designer / Server etc. there are countless solutions that aren't marked as such. Perhaps it would be helpful to automate a follow up email to the Discussion starter a few days after the final post just reminding them to Mark a Solution if their question has been solved.
PS/ not sure where I should've put this Idea because it doesn't relate to an Alteryx product. There didn't seem to be a category for Community Ideas as far as I could see.