SSL enables browsers to communicate with a web-server over a secure channel that prevents eavesdropping, tampering and message forgery. You should always use SSL for login pages where users are entering usernames/passwords, as well as for all other sensitive pages on sites (for example: account pages that show financial or personal information). Configuring SSL on Windows with previous versions of IIS has been a pain. Figuring out how to install and manage a certificate, and then associate it with a web-site, is something I bet most web developers don't know how to enable. The good news is that IIS 7.0 makes it radically easier to configure and enable SSL. IIS 7.0 also now has built-in support for creating "Self Signed Certificates" that enable you to easily create test/personal certificates that you can use to quickly SSL enable a site for development or test purposes. Using IIS 7.0 you can SSL enable an existing web site in under 30 seconds.