Activity of users on Internet discussion forums is analyzed. The rank of users is shown to be approximated better by stretched-exponential function than by Zipfs law. Cumulative distribution function is found as an excellent tool in analysis of the dynamics of the collective social phenomena. We are able to approximate the number of blog comments with time by simple functions that resemble Fermi-Dirac distribution function: probability of posting a comment is given by $P(t)=P_0(t) / (1+P_0(t)$, where $P_0(t)=exp(a \cdot log(t/t_0))$. It is argued that dynamics of blog entries by a specific user ought to be related to personality of each user.