[The preacher] began to discover one peculiar advantage belonging to the little open chamber of the pulpit—open not only or especially to heaven above, but to so many of the secret chambers of the souls of the congregation. For what a man dares not, could not if he dared, and dared not if he could, say to another, even at the time and in the place fittest of all, he can say thence, open-faced before the whole congregation; and the person in need thereof may hear it without umbrage, or the choking husk of individual application, irritating to the rejection of what truth may lie in it for him.
This passage from George MacDonald's Thomas Wingfold, Curate (chapter 7) applies not only to the pulpit, but also to the blog. The trouble with opinions, complaints, suggestions, and exhortations spoken in person (or e-mail, or text—anything addressed to an individual or a distinctive group) is that the hearer often takes the words personally, as directed towards himself, even when they are not. A blog post, on the other hand, is an offering, one of many in a smorgasbord, presented to the world so that one might take, and another reject the offering, in whole or in part, without offense to either the giver or the recipient.