The original and further detail, in French, can be found here. What this is essentially saying is that the socialists have the greatest number of conversations within the tightest knit community. It does not necessarily indicate influence, but can be read as reach perhaps. The pattern is largely static since 2007, Segolene Royal's Segosphere was fairly dominant, maybe contributed to her coming a close second, but is no indication of real political support or even of getting into the second round. What it does indicate though is that, online, each party (except the extreme left/gauche) has an active strongly networked hub of supportive webloggers pushing messages out.