4 ms·

GMail opens and caches links, and Chrome prefetches links, so enjoy your two "read" receipts on the link I never clicked.

• ffpip 3y ago
  if link fetched immediately: google_bot else: user
  • geor9e 3y ago
    A smart engineer won't be wasting resources by fetching immediately though. It will trigger by datacenter off-peak hours or by user activity.
  • jayjaychicago 3y ago
    Yes! The pickle is that the system doesn't know when the link is sent and if it was sent via email/sms/..., only when it's created. Something that helps is a deny list of user agents on the server for obvious things (like when iOS messages previews the URL) that have kept known user agents over many years. The problem with spam filters is that they don't want you to know they are spam filters so the user agents are hard to pin down definitively. Overall, that's why it gives the user 3 notifications. Hopefully, most folks will know something's off if they get a read seconds after emailing someone.