Is a smiley. The text representation (if you "hover" of over the smiley) is roflblack for some reason.
You must have "smileys" enabled in your profile to see them.
Look below the reply text box to four check boxes.
1) show your signature
2) Automatically parse links
3) Automatically retrieve titles from external links
4) Disable smileys in text
A check mark in the 4th box will put roflblack instead of a little guy laying on his back and side laughing.
Lou and Laura with Bella - German Short Hair Pointer
2008 GMC Sierra 2500HD Crewcab SB Allison Duramax
2010 Flagstaff 8526RLWS - Superglide 3300
HAM CALLSIGN - KC3FFW