I recently had a strange SharePoint experience, where a certain user would always find me logged in to SharePoint when he launched it!
On this users I had switched users within SharePoint once, so I could show him features he didn’t have permissions for. I then saved a Favorite in his browser so he could easily get to SharePoint and left his office. A week later, I’m in a meeting with the user and I notice I’m logged into SharePoint on his laptop!!!
After a little investigation, I come to discover IE8 caches credentials with the favorite! What on earth was Microsoft thinking?
To solve this, I deleted his favorite, logged into SharePoint with his credentials and saved a new favorite. Now all is good.