Earlier quoted context omitted.
Not an use-case I have currently for myself, but I thought that wikis and other services that host content written by third-parties would be better if they checked broken-links and notified visitors and content creators. Maybe my use-case is limiting my ability to think about someone paying for it.
How certain startups CMS based content could go checking broken-links? 1. They implement their own checker - fair enough, if they want to do it. 2. They use a micro API for it and forget about investing the time on it, if it works well for them.
Now I can imagine it :P