Office 365: Outlook Web App & Internet Explorer 8
Although Internet Explorer 8 is supported, it's important to note your end-users will get a far from ideal experience with OWA if they are using this browser version. We have recently published this KB article explaining the issue:
Slow Outlook Web App performance when accessed through Internet Explorer 8 in Office 365: http://support.microsoft.com/kb/2871314
Said in another way, friends don't let friends use Internet Explorer 8 to work in OWA, unless they are good with using OWA light.