But if they have the hash and its only been encrypted with something like MD5 its a fairly arbitrary process to reverse it.
Sure here it more secure but its not that long ago MD5 hash was considered secure so I bet there are many places who havent changed...
Anyway we are getting off topic.
vBulletin adds salt to the passwords so a hashes can't be reversed by brute force.
Back on topic (posted this on the MLR),it's related to the encoding. For Chrome it sends a compressed version of the site which works, but for IE for some reason it sends an uncompressed version which isn't a problem in itself, but it only sends a fraction of the page. If you change the user agent in IE to that of Chrome (F12, go to the emulation settings) then it gets the full compressed version and works again. But it's obviously easier just to use Chrome instead.