ANSWERED: Too many...
(1) dead external links on IMDb
There is no shortage of links to defunct websites, missing webpages or webpages lacking the relevant content, on IMDb. I recommend the creation of a renewal interface and automated removal of links that are not manually renewed within 180 days after being created or renewed. The problem with such an approach is more or less obvious, but it would reflect policy more so than technical resolution.
An alternative would be for a volunteer to host a bot that scans links for lack of relevant content and deletes the ones meeting the criteria. The problem with such an alternative approach is that links to sites or pages that have merely relocated will be deleted rather than updated. I don't yet know how to form an automated process that can determine the new location of a moved site or page, because the process requires judgment.
The bottom line: The dead links do no justice for users of IMDb. Why can't something be done about the situation? Is anybody besides me bothered by it?
(2) other things on IMDb
I'm sure there are other things of which there are too many on IMDb, but I'm not sure in what way contributors come into play, as of this time.