This not only advertises and helps brand you, but it is advertising without spamming.
This is especially helpful when you are on chats with large lists of people. Instead of using "Mike302" as your identifying nickname, you could use:
WipeOutPimples
SkinnyButtsForever
GangsterMoneyFund
IsYourBossAnIdiot
Got the idea?
People will remember you, and now you have a chance to deliver your message.