Jesus Christ. I know it's the internet and everything, but makaveli, LEARN SOME BASIC RULES OF GRAMMAR.
there- usually refers to a place. We're going over there, by the barn, to kill Phoenix Dark for inviting you here.
their- possessive. Maybe as in, "I realized I wasn't welcome when their opinions became known about me."
they're- contraction of they are. As in, "They're going to make fun of me for being such a mouthbreathing fucktard. Maybe I should go post exclusively on OA."