Why is there a red warning icon next to the sender of a discussion message?

In order to ensure that email sent in as discussion messages is from who it says it is from, Jiglu checks it for a DKIM signature. This uses a cryptographic signature on the message to check it hasn't been tampered with, in conjunction with a key in the DNS for the domain it came from.

When Jiglu finds a problem - for example because it actually came from a different domain or the text of the message has been changed - then it will display a red warning symbol after the name of the sender. If, however, the message was first checked by a moderator then the warning icon won't be displayed.