She Stalks My Twitter And Facebook?

[Hello]

Whenever I put a new picture as my profile picture on my facebook profile, my older sister will say to me 'like your new profile picture its so posy' sarcastically. Then she'll continue to tell my mom and dad that I have a new one. Everytime I upload a status (which isn't very often), she'll read it aloud for everyone to hear and she'll take the piss out of it. It seriously annoys me. Why does she do this? She also looks through all of my photos all the time, making a verbal comment on each one but not actually posting it on Facebook.
I have a twitter account and have 200 or so followers, and she has one too but she only has about 70. Almost every night she looks through all my tweets, making fun of me and telling everyone. She'll look through my photos, saying 'god thats posy' and 'you're so vain'. She has loads of pictures of herself on twitter but apparently they're not vain because she didn't take them herself?!
For example, the other night me and my family were watching TV after dinner and she's on her blackberry and she'll go, "Lets have a look at your tweets." And continues to read out every one of them. What is wrong with her?! Do you guys know why she is like this?! Sorry I've been wittering on for a while but please post your thoughts and suggestions below!
Thanks :)xx

[Derek]

No offence, and pardon my german, but she sounds like a right cúnt.

[Izzy]

Simply delete her off Facebook and change you privacy settings and change twitter to private and block her.
She's your sibling, they're all the same, annoying as f**k!

[Molly]

She could be jealous that you've got more followers than her, I know quite a few people that are jealous of how many followers I have! Just block and delete her off facebook, on twitter though you can still see peoples tweets even when you've blocked them, it's stupid, so the only way you can fully get rid of her on Twitter is to change your privacy settings! But that means that people have to ask for your permission to follow you:/ Hope any of this could have helped you

[M M M]

Grab her Blackberry and smash the thing up, job done, superglue the bog seat just before her morning crap, then phone the fire brigade to get her out, she wont bother you any more.

[nora]

Well you could post stuff about her. Such as my sister is wearing, XYZ or why does my sister always have to go to my twitter page and read it out for my parents, etc. hahaha. I would have some fun with this. She is probably jealous or insecure cause you are younger.

[Cat]

This is so annoying, my family did it too.
I deleted them all off facebook and made my tweets protected, block her on twitter so she can't read them.
You don't have to take that kinda crap from them -_-
Good luck.