Reading agent blogs is usually quite enlightening. You get into the mind of the agent to find out what they really think, and that can help (I suppose) to finally land that particular agent for your novel. Grain of salt alert - what one agent proclaims as law may not be what another agent believes at all. Improve your situational awareness before rolling in on your target.
But reading the comment sections of agent blogs is usually an embarrassing tour through the museum of total ass-suckery. Two recent examples of advanced salad tossing evolutions here and here. It really is enough to make you ashamed of the human race.