Changes made in November 2005 on the version of the MediaWiki software running Wikipedia altered the way signatures work. If your signature is not working now (but was working previously), you will need to make some changes to your Preferences page.
MediaWiki makes the creation of simple, straightforward signatures relatively easy. For example, if User:Example wants a signature that displays as Example, he would simply have to enter "Example" in the Signature field in Preferences. The software automatically places "Example" in [[User:Example|here]], to form [[User:Example|Example]]. When saved in a page, this markup displays as "Example". Wiki markup and HTML markup do not function in the Signature field, unless the "Treat the above as wiki markup" option is checked in Preferences.
For example, placing the following in the default Signature field
will result in a signature that looks like
This is because Wiki markup (and HTML markup) are now escaped as HTML entities when placed in the default Signature field, e.g. [ instead of [.
If you would like a signature that requires markup within the Signature field, please check the "Treat the above as wiki markup" option and enter the full signature string into the field.
For instance, to produce the signature
within the Signature field and check the "Treat the above as wiki markup" option.
If you have been using "raw signatures" all along but find that your signature is now not working, you may find the following message displayed in your preferences:
This means you are using invalid markup on your signature. Some possible causes with their corresponding solutions:
Remember that all wikilinks show up as bold black text on the page they link to. So if you are testing your signature on your userpage/talk page and the user/talk part of it doesn't show up as a link, that may be why.
The markup for your signature is visible in the edit window; if it is too long, it makes editing the page harder. Try to keep the markup length below about one line of text. Also, the signature length is, since 13 June 2006, restricted to 255 bytes (bug #8458, r22960), later changed to 255 characters (bug #10338, r23389).