As a member of a debating team in college, and as a participant in many formal and informal debates, I have learned one thing:

Someone who has a factual or logical argument presents it without being asked, right at the beginning of the discussion.

Those who lack such an argument, or who lack the skill to construct one if they had the information, generally resort to various tactics designed to obscure the fact that they have nothing.

These include, but are not limited to:

Personal attack of the opponent, on various levels;

Unsupported claims of intellectual superiority, thus entitling them to a “win” with no facts or logic;

Changing the subject;

Blaming others;

Justifying their own bad behavior with the claim of bad behavior on the part of others;

Appeal to authority, usually with misquotes, mischaracterizations or cherry-picked, out of context snippets.

etc, etc....

Most of this is quite common on the blogosphere.