A couple of days ago I received an email from our MOSS farm indicating that a user had exceeded their warning level for storage. When I tried to visit the user's My Site the site would not render properly.
What I wanted to know was what was taking up so much space but I had to deal with getting the site to render properly first. That was a simple fix – increase the user’s my site storage limit via the Site Collection Quota and Locks in the MOSS Central Administration. I customized the user’s quota by adding 5 MB to the maximum storage limit. Following this change, the site rendered as expected.
Going back to the primary question, I visited the user’s My Site Storage Space Allocation Page via the site’s Site Settings page. The direct URL would end in /_layouts/storman.aspx on the user's My Site. Here's what the page looks like:
There it was. The issue was in the Shared Documents. I changed the view to Documents and was reminded how big PowerPoint presentations can get.
One last note, I was able to administer the user’s My Site because I too was a Site Collection administrator on the user’s My Site. Without adding that extra level of access, the user that created the my site would be the only Site Collection administrator.