A permalink remains unchanged indefinetly (Wikipedia). As a user I need a way to send permanently available links, that do not die when the page is updated, changed or moved in the system. In the best case those links should have a readable format that allows the user clicking the link (e.g. from an email) to anticipate, where it's headed. I a good solution, this permalink is directly accessible in the address bar and needs no specific retrieval from a "permalink"-section.