Rain's official fan club's name is The Cloud. He named it personally and it does complement his name, right? The official color of this fandom is silver.
If you want to sign up for The Cloud, just visit http://rain-cloud.co.kr/
We support our fellow Clouds in our projects for Rain. Here are their websites. Make sure to visit and support them, too!
Cloud USA - http://cloudusa.wordpress.com/
memo-rain - http://memo-rain.ning.com/
Cloud Ruby - http://rubyannmalasig.wordpress.com/
Incredible Rain (Cloud Hungary) - http://incrediblerain.blogspot.com/
Rain's Little Cloud - http://rainslittlecloud.blogspot.com/
Rain Legend - http://www.rainlegend.com/
Jung Ji Hoon - http://jungjihoon.wordpress.com/
Rain 비 Ji Hoon (Rain Germany) - http://www.rainjihoon.com/
Rainthetreasure - https://www.facebook.com/pages/Rainthetreasure/154037571410717?fref=ts
RAIN harudoful's blog - http://ameblo.jp/naturally0107/
If you have a page dedicated to Rain, just comment below and I will add it to this list.