Hi Tracy,
If it's me you are asking, the reason is as follows. When I first joined the site I was simply Colin and there was another gentleman ColinE.
However, another solver started signing himself as Colin so I posted a note to say I was adding Swansea Jack after my name to differentiate between the two of us.
I could sign myself just Swansea Jack but I'm quite attached to it now.
Blessings.