That's what that was!? I aways wondered why some people would end their emails to me with "J". At first I thought it was a typo, then I thought it was just some encoding issue. Never knew I was missing out on smiles.
I'm called James so when I got a "Thanks J", I thought they had taken it on themselves to give me a new nickname. Perhaps signing off my emails with "Thanks :)" gave them sane impression.
Strangely felt better when I realised it was a smiley face.