  This is mostly* a non-technical exposition of the joint work arXiv:1212.0373
with Caporaso and Payne. Topics include: Moduli of Riemann surfaces / algebraic
curves; Deligne-Mumford compactification; Dual graphs and the combinatorics of
the compactification; Tropical curves and their moduli; Non-archimedean
geometry and comparison.
  * Maybe the last section is technical.
