I have seen your question in the New User Welcome board. :>
A supporter like myself, is someone who donates a certain amount of money to improve the wellbeing of the community. The money we give helps to pay fees that PC needs to pay in order to stay up and running. It also goes towards making sure PC's servers does crash every like 2 seconds. :P
With donating you get an italic'ed blue name and a supporter tag. Depeding on the amount you donate, dpeends what tier you are. The more money you donate, the higher the tier. The highest tier is 6.
Another goodie from bcoming a supporter is that you recieve something called perks. Perks are gifts back to those who help PC by donating. Some perks include, a blog, larger avatar, more Private Messaging space and so on. Also like tiers, the moremoney you donate or the higher the tier you are determines what and how much perks you are eligible to recieve. :)