http://hubski.com/about

I'd recommend that you don't rely on only color for the post and following telltales. Use color plus something else.

    u->oscar
    oscar->u
    u->oscar->u

For the not shared, shared, and yours icons, in addition to color you could:

    Not shared: only the center circle, no surrounding dots.
    Shared: center circle plus surrounding dots.
    Yours: center circle, surrounding dots and a line circle around that.

Extra fancy if Yours icons only get dots (inside the line circle) if they're shared posts.

EDIT: Formatting.