What kind of sister is this?

[Beletje_vos AM + VT]

I'm not a twitter person. My older sister has one. I just checked out her twitter page and constantly she talks about me and only in an insulting manner. Saying I wanted to be the attention of everything, am ignorant of such and such, have said a "few gems". So am I never allowed to speak? She'll just "tweet" what I say to her friends? What's with the lack of privacy and the complete rudeness about me? What's her problem? My parents are completely unaware of this and her lies being told about me.

What would you do in such a situation? Revenge? Show your friends your sister's mean comments about you and have them write on her page about how stupid she's being? What?
Ignoring her won't stop her from making me sound like a horrible person to her friends. This negative obsession with me has got to stop.
"When you both grow up you will stop doing this to each other."

Um. I haven't even done anything. And she's almost 26. I thought she was better than this childish behavior.