Hi Val and welcome aboard!
It's just a fun way of showing the length of time and the amount of posting members do on the board. We start with "in the green" (imagine your arrow in the grass), and work from the outside of the target in (white, black, blue, red and gold).
You'll also notice that some members have custom titles under their names. Those are our subscribers, who pay to help with the running of the forum, so they get some extra treats.
Hope that clears it up for you!
