I've changed my forum avatar twice in five years. Once when I bought the Dharma Initiatives, once when I rebuilt the DI as the 8-bit NES team. Your forum avatar is a brand, like your agent name. People who change theirs often lose brand awareness unless they make a concerted effort to remind people that they made the change. Some people make the change because their product is so toxic that they can't continue under the old name.
I learned that from business school... or maybe watching the Wire and it was about how to sell an inferior product in an ellastic market...
