Secure Socket Layer (SSL) helps keep communication safe from those looking to gain unauthorized access to, or manipulate, private data. It does this by encrypting the information that users enter as it flows to your databases. Browsers are making it more obvious to users when they're accessing a secure site and when they aren't.
People feeling safer leads to higher conversions. How, you may ask?
When a user knows their information is encrypted, they are more likely to trust you with personal information. This includes emails, credit cards, etc. Browsers are making users far more security conscious. If your destination pages are not secure, the user is less likely to join. But if your starting pages are not secure, users are becoming less likely to even click through.
So how do you get a sexy - and secure - site?
Our friends at 1and1 hosting have a step-by-step guide to converting your existing site to SSL. While some of their information is specific to their hosting platform, the bulk of it is relevant no matter who handles your domain hosting.