This is a quick review as to how one reader believed Priligy (dapoxetine) overcame his erectile issues. Now keep in mind that this class of drugs, in general, is filled with negative side effects and will likely cause long term health issues. Furthermore, Priligy is not even approved yet in the U.S. for any usage whatsoever.
However, I did want to discuss what this reader wrote - I got his permission of course - because his reported results were so dramatic and it brings up some issues with respect to psychogenic (psychological) erectile dysfunction.
Here is what he wrote. You'll immediately notice the enthusiasm:
READER: "First let me tell you about Dapoxetine (brand name Priligy). See, I can get a full erection with stimulation, I just can't keep it for more than 5 seconds without stimulation. I also have to stay on the edge of climax to have and maintain a full erection, problem has been that when I'm inside a woman and I get to the point of climax I have to slow down."
"The problem with this is that sometimes slowing down means my erection starts to go way, then it becomes clear that I'm losing my erection while inside a woman, it becomes psychological and then the battle is lost."
"Met a very fun and open minded girl, took a 10mg dose of Cialis and a 30mg dose of Dapoxetine before sex, this time instead of having to slow down and risk losing my erection, I was able to just keep going, and going, and going. It was the first time in about 7 or 8 years that I've really been able to knock a woman's socks off sexually."
So what is Priligy? Could it really have cured 7 or 8 years of erectile dysfunction?
What is interesting is that Priligy is actually used in much of Europe for premature ejaculation, not erectile dysfunction, and it has several studies behind it in this area.  Furthermore, Priligy is an SSRI and SSRI's are notorious for actually causing erectile dysfunction. In fact, seratonin is actually a vasoconstrictor, i.e. it will often contract your arteries and reduce blood flow (to your penis). 
All of that said, though, one cannot help but wonder if there is something unique about this drug that may be applicable to certain men. The reader's comments indicate that psychogenic (psychological) issues definitely played a role in his erectile dysfunction. One of the most misunderstood aspects of an erection is the mental and nervous system component and we can only hope that more research will follow in these areas.
CAUTIONS: This drug does have significant reported side effects: "common adverse events (30 mg and 60 mg dapoxetine, respectively) were nausea (8 7%, 20 1%), diarrhoea (3 9%, 6 8%), headache (5 9%, 6 8%), and dizziness (3 0%, 6 2%)."  In addition, some experts feel that SSRI's can raise cortisol and, in the long term, potentially damage arteries.
1) Ther Clin Risk Manag, 3(2):277 89. "Dapoxetine, a novel selective serotonin transport inhibitor for the treatment of premature ejaculation".
2) The Lancet, Sep 2006, 368(9539):929-937, "Efficacy and tolerability of dapoxetine in treatment of premature ejaculation: an integrated analysis of two double-blind, randomised controlled trials"
3) Journal of Clinical Psychiatry, Feb 1993, 54(2):71-72, "Vasoconstrictive effects and SSRIs"