... when an item is being offered.

Is this a new procedure to insure consummation?

I only ask since I have e-mailed one or two sellers saying that I would take the item advertised here; received their (what I thought was final) response, but later see a "SOLD" in red by someone else.

Though I'm sure private e-mailes are still in order (it seems to be the case when I offer an item, anyway), I'm just wondering which is generally more acceptable, and why...

I recently postd a item and when I was e-mailed by the buyer I posted a sold message below my post; and a poster asked "Did you buy your own chip?" Not sure if I was being reprimanded. Thus I'm wondering if the "SOLD" post by an interested buyer is important/"official;" especially if a buyer does not wish to inform others that he/she bought the item.

Just curious. Private e-mail is okay.