Some of my mails are showing this icon in Outlook 2007. When I click it, it takes longer time to load the content, what does this icon mean? I couldn't find it in the Microsoft Office help docs..
Although I am unable to find that exact icon, it appears to be a shortcut icon. Very possibly an icon for a message which has been archived outside the actual data file. If that is the case, it would explain the delay in displaying the message when you click on it.
If you are using custom forms or add-ins, they can change icon sets too. Therefore, this may be one of those. I found this one, which looks similar;