[pbhjpbhj]

Deletion by flag is very common in IT and presumably has been since the first undelete program was created. It's not a Facebook thing.

Some mail programs for a long time have had a soft-delete that requires an expunging process to create compete removal.

In an IT setting you can delete a blob from a db, but it might still be on disk, and it will still be in caches, on user machines, and in backups/archives.

[mic47]

Because FB deletes by flag so that content disappear instantly and then start the actual process of deletion (which can take while because of stuff like backup, cols storage)...