TwitterScope a visual search system that streams, stores, clusters and visualizes tweets related to any keywords (the public version only tracks a set number of keywords) (unfortunately the website is no longer in existence due to my move from AT&T to Yahoo!)

GMap an algorithm for visualizing clusters and relations. In Graphviz

sfdp a force directed algorithm for large scale graph drawing/graph layout, with state of the art overlap removal, in Graphviz .

GraphPlot, GraphPlot3D, TreePlot, LayeredGraphPlot functions for graph drawing/graph layout in Mathematica.

FindMinimum a function for nonlinear constrained optimization using nonlinear interior point method, Mathematica.

LinearProgramming a function for large scale linear programming problems using interior point method, Mathematica.

FCAT -- a tool for the coverage analysis of FORTRAN.

MONET -- a software which orders a unsymmetric into (single) bordered block diagonal matrix.

JASPA -- how does Java perform compared with C and F90?