Pajek is a program, for Windows, for analysis and visualization of large networks having some thousands or even millions of vertices. In Slovenian language the word pajek means spider.

The main motivation for development of Pajek was the observation that there exist several sources of large networks that are already in machine-readable form. Pajek should provide tools for analysis and visualization of such networks: collaboration networks, organic molecule in chemistry, protein-receptor interaction networks, genealogies, Internet networks, citation networks, diffusion (AIDS, news, innovations) networks, data-mining (2-mode networks), etc.

UCINET is a comprehensive program for the analysis of social networks and other proximity data. The program con-tains dozens of network analytic routines (e.g., centrality measures, dyadic cohesion measures, positional analysis algorithms, clique finders, etc.), stochastic dyad models (P1), network hypothesis testing procedures (including QAP matrix correlation/regression and categorical and continuous attribute autocorrelation tests), plus general statistical and multi-variate analysis tools such as multi-dimensional scaling, correspondence analysis, factor analysis, cluster analysis, multiple regression, etc. In addition, UCINET provides a host of data management and transformation tools ranging from graph-theoretic procedures to a full-featured matrix algebra language.

SIENA (Simulation Investigation for Empirical Network Analysis), is a computer program that carries out the statistical estimation of models for repeated measures of social networks according to a dynamic actor-oriented model. Networks here are understood as entire (complete) networks, not as personal (egocentered) networks: it is assumed that a set of nodes (social actors) is given, and all ties (links) between these nodes are known - except perhaps for a moderate amount of missing data.

NetDraw is a program for drawing networks. It uses (or will use) several different algorithms for laying out nodes in 2-dimensional space (3D will come later). Netdraw reads UCINET system files, UCINET DL text files, and Pajek text files (.net, .clu and .vec). It can save data to Pajek and to Mage. It can save diagrams as EMF, WMF, BMP and JPG files. It can also print directly from the program at high resolution (much better than printing document containing embedded graphics).