"When you delete your account, people won't be able to see it on Facebook. It may take up to 90 days to delete all of the things you've posted, like your photos, status updates or other data stored in backup systems".
Why the writer says "delete all of the things" not simply "delete all things" ?
what is the difference ?
I see this structure appears many times in English but have no idea why is that.
Is there any rule here?