Check mailbox size and usage in OWA

We run the Outlook Web Access component of exchange to allow our users webmail access. In OWA it's not immediately apparent how to check the size and usage of the mailbox. My initial google search turned up an forum post from 2004 which states that this isn't possible without a third party product. After browsing several other articles however I discovered that all it takes is to mouseover the mailbox name and a popup will present mailbox size and current usage. This feature is only available in the non-light version i.e. IE only. This page was where I initially found instructions. Hope that helps!