Social Network sites: Going up - Going down

PLEASE CLICK ON THE IMAGE TO ENLARGE

digg [blue] vs. stumbleupon [red] vs. del.icio.us [olive] vs. reddit.com [green] vs. propeller.com [black]

Who will survive the hype in the long run? Interesting how the graphs of del.icio.us and digg mirror each other. Have both of them reached their saturation points already? Looks like it. Of course you have to ask yourself how accurate the Alexa data is.