Justin’s FUEL fix will help add-ons avoid leaks and shutdown hangs: bug 750454.
Vladan blogged about first results from our non-destructive chromehang. Last year we briefly caused our nightly to crash if it hung for over 30seconds, which got us a lot of useful data (and some of the initial snappy bugs). This piggybacked on our crash-handling infrastructure so it was a very effective experiment (a bit brutal though). Vladan spent time this year working on plumbing to get the same sort of data non-destructively. As a result we are looking to turn on frame pointers in nightly builds and dial down hang detection to 5 seconds (bug 763124).