From the Portal Wiki
Custom signatures allow you to overwrite the default signature (The text that shows up when you type ~~~~, or hit the signature button).
Creating a Custom Signature
- 1. Navigate to User:USERNAME/Sig
- Note: Replace USERNAME with your Portal Wiki username.
- 2. Edit the page, and include everything that you want to be in your sig. For example, to recreate the default signature, you'd add something like:
- 3. Save the page
- 4. Go to Special:Preferences
- 5. In the "Signature" field, add the following:
- 6. Check the box marked "Treat signatures as Wikitext (without an automatic link)"
That's it. Next time you use ~~~~ it will be replaced with the contents of your /Sig page.