I heard a Posek who answers questions both in person and online and he said the online anonymous questions were of a very different nature than the in person ones. The questions he got online are the type he never go before as in person posek and he didnt think those people would ask these questions if there wasnt an anonymous online forum
People will ask the Rav in person if the pot is Kosher, but they much rarer ask the taboo question in person.