Most people horridly abuse/misuse meta. Suffice it to say, a lot of people throw out statements like "Oh, so-and-so should know that this is not my scum meta" and for some bizarre reason people tend to swallow it without chewing. See my sig: as soon as a person knows their own meta, it becomes useless. Like that scene from Casino Royale where Bond thinks he's got a great tell on Le Chiffre but then Le Chiffre uses it to clean him out.
It
can
be a powerful tool but I find that 99% of explicit meta mentions I see are fallacious.