Having experienced something slightly similar over the past couple of days with Pprune, and taking a wild, wild guess I'd initially check what's timing out on these sites: possibly third-party content from an ad server. Then, I'd wonder if that content were Flash-based. Running a mix of browsers which block somewhere between everything and nothing, the latter are having the problems currently. As Keef says, the event log is your friend. So is Fiddler.