Chris Remo from Gamasutra writes:
"A new study by analysis firm DFC in conjunction with social media company GamerDNA has extensively compared Left 4 Dead user activity habits across PC and Xbox 360 -- and finds Valve's strategy of combining promotions and free updates may extend a game's shelf life dramatically.
Results of the study were released in the latest edition of the DFC Dossier publication, and are based on the activity of over 180,000 PC and Xbox 360 gamers via Steam, Xbox Live, and Xfire from the time of the game's release until May."