I am currently doing this by generating an email address that managers can 'cc' while emailing any feedback to their team members.
All the feedback that is collected is visualized as a timeline which the managers can access at the time of annual/semi annual performance review to know the evolution of the team member, the little wins and course correction feedback that was given out to him/her.
I am giving it to a handful of managers to try it out and yet to make a page for it.
What do you people think about it? If you want to try it out, I have an old page to register for it. You can enter in your details and I'll generate the email key for you: http://52metrics.com/redcarpet