Does anyone know what the symbo;s to the left of topics stand for. Green or grey crosses, black and green dots, flashing and combinations of above?

The gray cross means means there are new posts. The green cross there are no new posts. (this is at the bottom of the home page.) But I don't know what the flashing black dot in a green cross means.

Oh, I think the black dot means you have posted in that thread. Maybe.