[Push Pin] What's the purpose of this feature?

G'Day from Australia to all,
I'm after info again and it shouldn't be a too difficult a problem for the experts out there.

When you select "Send/Recv" in Outlook Express, a window opens and it shows a bar graph indicating the download/upload progress. If you select the <<Details button the accounts you have are also displayed. At the bottom righthand corner of this window, there is an icon of a push pin, if you click on it it changes it's orientation.

What's the purpose of this function?

 

Thanks for your reply Pete. I find it's safer to ask these doppy questions rather than just go ahead and do it, then wonder why the hell something doesn't work as it use to!!!