To create a signature, follow bitcointalk's standards and use their signature builder, available in a "profile" section of the forum.
To get the resulting HTML, you will have to do some odd things. First, add the signature to your profile. Now all your posts should have it (and yes, you can not use this approach to create a signature for a rank that is higher than your current rank). Use "View document source" option of your browser to see the HTML code. DO NOT use "Inspect" option, as it adds some extra formatting.
You will see your signature in the page's HTML:
...
ICO Dev. Kit (
https://duke-of-ether.com)
...
Here "1467940" is your (actually, my, it is different for you) user id. Keep in mind, that any extra space or carriage return will make a different signature, so our scanner will not recognize it. It can be a challenging task, as senior forum members can have a very complex signatures: