- Domain Expired and Ads Page is appearing.
- Site is offline and Page not found status.
- Page is redirected to some other website or page.
- The page content are changed and now showing your link
- It is showing some search page
In such circumstances your links is offline and the question arises
- Should you send a mail to site owner for removal? – NO USE
- Should you Leave it without doing any action? – Think
- Should you include the URL or domain in Disavow file? – Yes
Most of webmaster/SEO will advocate not to do anything with such links and no need of even disavow it. I have different opinion it is better to be safe and include in disavow file to prevent damages that might comes in future in the page is activated and link reappears.