Nothing in particular. If you just go to the D-word site and do nothing it has a tendency to crash. Sometimes even before you get a chance to log in. Sometimes it crashes sooner, sometimes later, but it always crashes if you stay on the site for more than a few minutes.
I assume there have to be some coded operations taking place in the background of the site that cause this, because it can happen while the site is just sitting there, without any user action. Sometimes it becomes VERY slow on basic operations like text entry and then crashes.
Maybe borrow somebody's iPhone and take a look?