Scott Hanselman posted a while back about a browsers definition problem with some ASP.NET sites that causes problems. Microsoft has articles on this also. Having just received my BUILD tablet that includes IE10, I tested the Silicon Valley Code Camp web site and discovered that when you login, then switch to another page, the login did not stick. After uploading the two files Scott mentions (firefox.browser and ie.browser), the problem goes away.
Thanks Scott for the heads up.