Safari has no secure site indicators for popup windows
Most bank websites (at least in Turkey) open a popup window to get your credentials. I realized there is no way to tell if HTTPS is used if you use Safari.
Here are some screenshots: http://i.imgur.com/71G2Z.png http://i.imgur.com/vHQEa.png
This is very dangerous since it is not very hard to use mitm attacks to redirect user to a similar unsecure website.