  A model for crack propagation and contact line depinning is studied. Although
the model contains nonlocal interactions, it obeys general scaling relations
for depinning via localized bursts or avalanches. Our numerical result for the
roughness exponent in one dimension, $\chi=0.49 \pm 0.05$, agrees with recent
experiments on cracks measuring the in-plane roughness $\chi \simeq 0.5 - 0.6$,
as well as mean field arguments giving $\chi=1/2$, but is significantly higher
than the functional renormalization group prediction $\chi = 1/3$.
