Quies

Since your post in the rate thread is a bit off topic I figured I would drop a response here. You set your signature under Account Settings. I don't recall if there is a minimum post requirement for the feature to unlock or not.
 

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Avatar and Signature

If a moderator has edited your post or changed your signature, do not revert it back. We did it for a reason.

Your signature may contain one embedded video, so long as it is within spoiler tags.

The maximum file size for avatars (uploaded or linked) is 300 Kb.

Signature images can be no longer than 550 pixels and no higher than 300 pixels. The maximum size is 300 Kb per image.

Signature images larger than the specified size, may be included within spoiler tags.

Your whole signature (including text/image etc) must be no taller than 300 pixels. Spoiler tags can help reduce your signature.

The total of all images in your signatures may not be greater than 600kb.

 

From the Guidelines thread.

I think the rules are in the setting panel where you change it, but figured I would quite the rules just incase.