for - Link rot study - on NY Times archive - show how pervasive it is - stats - link rot - NY Times study - digital decay - link rot - internet is ephemeral - dead links

for - digital delay stats - Pew Research

summary - That digital decay and link rot are digital facts of life means that annotating information on the page that is relevant for you to preserve is a good practice. - It may appear redundant but if that page disappears in the future, you will be glad you have preserved it in a place accessible to you - in your annotations!