Largest Semicircle Inscribable in a Unit Square
I found LaTeX useful for presenting a solution in the Math Problem Solving group on Mathematics24x7, in the question largest semicircle inscribable in a unit square. The same question, asked in "maxima & minima" (2 pages) on an Orkut.com mathematics community, shows the limitations of a text only forum for discussing math.

Testing Math Markup
Bob demonstrates that WikiSpaces has LaTeX capability, on his wiki at http://afwings.wikispaces.com/