I think the way to get a web address clickable in a signature is to use html formatting,
AND
WLM 2011 seems to add a space automatically after the signature website address. I found that by deleting this space and then placing a manual carriage return (press enter) after placing the signature in the message, the signature website address is clickable. I have been unable to do this in the actual signature window itself.
I have found that even in messages formatted in plain text, adding that extra carriage return (pressing enter) makes the signature website address clickable--in most cases.
I experimented with this by sending test emails to comcast, yahoo and aol. Only the yahoo email's website signature was not clickable in plain text.
977 GB Western Digital WDC WD1001FAES-75W7A0 (SCSI)
Antivirus
Windows Defender, MalwareBytes Anti-Malware, AdwCleaner
Browser
Firefox, occasionally IE and Edge
Other Info
Mozilla Firefox, Mozilla Thunderbird. Western Digital Passport 250 GB external HD, two Mushkin Enhanced Mulholland 32GB USB flash drives, AKG K240 Studio headphones, Asus AC-1900 dual band wireless router.
...the URLs I had in my website were not clickable, SOME of the time. It seems that if I have "Plain text" showing in the "New Message" then they will NOT be clickable and it it shows "Rich text" they are. I want them all, to always be clickable no matter which email addy I send from, and all replies as well.