What does this mean (Twitter question)?

[{αngelα.lee}ღ]

Hi, I'm thinking of creating a Twitter account but I was wondering what this meant:

So I was viewing a friend's Twitter profile, and it had things like, for example, @Marie how was school?

Does that mean he commented/replied to Marie or did Marie comment/reply back to him?

Thanks!

[I M a Show Stoppa]

it means that your particular tweet is for Marie

[gentleturkey698]

"at Marie how was school" so he is asking Marie.
he commented/replied to Marie

[some kid]

Your friend was talking only to Marie. So when he puts the @ sign before her name it shows up in her mentions so she can read it and write back.