Figure 3

Correlations between different activities in aNobii. Left: Average number of group memberships $〈n_g〉$, of books in library $〈n_b〉$ and wishlist size $〈n_w〉$ against the number of social out-links $k_{\mathrm{out}}$. Right: Average number of group memberships and tag annotations $〈n_a〉$ against the number of books in the library.