PLOS ONE study on the rise in scientific retractions

Still on the subject of retractions, a recent study published in PLOS ONe by R. Grant Steen, Arturo Casadevall, and Ferric C. Fang asks why are the number of scientific retractions rising?   Is it because the number of flawed articles being published are increasing, or that they are being retracted more quickly?  Click here to read the article in full.