As to the links, I suppose I could consider installing a "broken link checker", link this one, on older sites, even blogs. You can read the pros there for using them. I get a lot of emails and tweets from SEO and other website services, and get so wrapped up in "news" and current projects that I don't respond to them often.
I can even imagine that in the future, web hosting companies or service providers could feel some incentive to monitor the quality of visits that websites and blogs, especially run by amateurs, receive from the public. That could involve metrics like bounce rates, depth, distinct visitors, and new visitors. They could also become concerned about the quality of links and their management. But that speaks to a more authoritarian kind of world where speech and broadcast is not as spontaneous as it is today. Sounds like China.