Here are three great quotes. Two are from Charles Spurgeon. One is from Doug Wilson. For these, see Doug Wilson's "Spurgeon On Anonymous Attack Blogs."
"Never write what you dare not sign. An anonymous letter-writer is a sort of assassin, who wears a mask, and stabs in the dark. Such a man is a fiend with a pen. If discovered, the wretch will be steeped in the blackest infamy."
In response to Lawrence, Doug Wilson clarifies:
"We are talking about people who want to slander the character of godly pastors with impunity, and with no accountability whatever. In fact, they are so averse to accountability that when they start to experience it they call it despotism. Which just shows how much they hate it. They seek anonymity, not because they want safety for their persons, but rather because they want safety for their sins."
Here is the second quote from Charles Spurgeon.
"When a man endeavors to take you in by religious talk, he imitates the devil, of whom the French negroes say, that when he wants to get a man into his clutches he talks to him about God. Very hateful is this trying to make gain by the false pretense of superior godliness."