Internet Explorer 7 users are redirected to the Mobile Express website (https://<org>.crm.dynamics.com/m) when attempting to access Microsoft Dynamics CRM Online after the December 2012 Service Update.
Internet Explorer 7 compatibility was removed in the December 2012 Service Update. As a result, all requests to the Microsoft Dynamics CRM Online website from Internet Explorer 7 clients will be redirected to the Mobile Express website. This is the expected behavior for all unsupported browsers.
Use a compatible browser to access the Microsoft Dynamics CRM website as described in the following KB article: