However, rather than displaying proven psychic ability, these individuals, Praagh and Edwards particularly, demonstrate no level of connection with the dead beyond that which closely resembles a technique that is centuries old called "cold reading." (Browne uses cold reading also, but also stakes out psychic predictions unlike Praagh and Edwards, although these wild pronouncements rarely have their veracityascertained.)
Cold reading boiled down to the most simple (and not its best) definition is eseentially using some basic psychology, making sweeping generalizations and guesses, and imploying some statistical likelihoods on individuals eager and willing to make and give importance to whatever strands of connection they can make out of these guesses to their deceased loved ones. This gives the appearance that the psychic has knowledge about facts, people, and situations that the psychic would not otherwise know or be able to know unless s/he was actually in touch with the dead.
Why do I care? Well, many of these people are making money off of the hurt and pain of individuals who have lost loved ones; others make wild claims that give false hope or hurt to people (like Browne's latest(and one of her most egregious) incorrect "prediction" of the death of Shawn Hornbeck, who later turned up alive); and they're just liars and I hate liars. If they claimed to just be entertainers with no real ability, I wouldn't care, but they claim true powers and abilities (all the guise of helping people) that they can't prove in controlled situations. They can't even prove them in self-controlled situations, with numerous incorrect guesses that don't rise above anything you or I could do.
I also believe that understanding how our own minds can deceive us and how our desire to want to believe certain things can color the way we take in and process information is vitally important to us in this day and age where our government keeps inching towards the newspeak and controlling eyes of Orwell's distopia and where we cannot rely on our media outlets any longer to bring us objective, well researched, factual and/or relevant news any longer. So understanding how this small sector of our society works informs us about greater and larger issues and how we should, could, and probably are approaching them.
In short, don't believe anything you hear, read, or see without knowing the facts behind it (and beware of whose "facts" they are).
A better definition of "cold reading" (along with other important associated concepts from The Skeptic's Dictionary)
Cold Reading Bingo (the most common techniques used in cold reading)
Professional Magician analysis of John Edward (humourous but serious analysis and some excellent thoughts on skepticism and beliefs in psychics by Ian Rowland)
John Edward reading analysis ("lay person" analysis - a little long)
Video presentation of James Van Praagh cold reading techniques (two parts - watch both)
Stop Sylvia Browne website
New Yorker article comparing criminal profiling to cold reading (by Tipping Point author Malcolm Gladwell)
Related: Book review of Carl Sagan's The Demon Haunted World
Other resource: The James Randi Educational Foundation