There might be a thin guise of "security" (i.e. email isn't a secure place to send your top-secret inbound message) but I'm inclined to suspect the main motivation is to drive people back to the platform and drive up their stickiness metrics.
For Facebook, the worst part is that it shows more in the gmail message preview than it shows when you click through to the message. There is no security explanation for that; it's clearly deliberate manipulation.
It is not just Facebook and LinkedIn. I've seen this from random small sites.
Some other silly shit that come to mind - having the unsubscribe link after half/full page of white space, once you click on unsubscribe "give us 24 to 48 hours to remove your email" etc. Really? they need 24 hours to delete (or change a flag) in the database?
Sometimes it’s some freaky ETL script that runs daily to put your address in a marketing message integration system. Not that it’s a great excuse, just usually more than a single flag update.
There might be a thin guise of "security" (i.e. email isn't a secure place to send your top-secret inbound message) but I'm inclined to suspect the main motivation is to drive people back to the platform and drive up their stickiness metrics.
It's user-hostile.