Any particular signs I should be aware of.
I know if she posts links to "our song" it is a good sign :)
Most Helpful Girl
If she is not an idiot, and we hope she isn't... she won't post anything stupid on her facebook/whatever page if she misses you, but will pick up the phone and call you. However, you can see if she is still hurting, angry, bitter over the breakup - there will be posts like 'Finally single! Yey!' or 'Love is bullshit' or any relationship/love-related stuff and quotes about ignoble/lying/manipulative people... meaning you... That doesn't prove she is missing you but proves she has unresolved issues regarding the breakup and regarding you, so... if there is any kind of emotion, that's a good sign that she is regretting that things ended.