If the little green dot next to the member's username is lit up, he's there. If not, he's either invisible or offline. No reason to bump the thread.
That does not by itself sex the plants. It merely speeds up the transition from veg to flower, particularly if the plant has been given a dark period during its veg time.
I would also use that method to jump-start flower on a plant that I intend to put outdoors very late in the season (1 August) to guarantee that flowering is initiated immediately.