Oh, you get those when you donate money to the forum. XD
It's ranked, so Tier 1 is $0-5, Tier 2 is $6-10, or something. I'm not sure of the amounts exactly. But I donated $20 Australian, which is about 16-17 dollars American, which made me a Tier 3 Supporter. You get benefits for donating too. XD
http://www.pokecommunity.com/showthread.php?t=25461
That's the Donation page, it provides information for people looking to donate and how to do so, and how much to donate for each Tier.
Hope that helped. XD