SSL is an acronym for Secure Socket Layer. It is a protocol used to secure communications between two computers on a network via data encryption. When used on a website, it is initiated by visiting a URL using the HTTPS protocol.
If you are planning on collecting sensitive data such as user or payment information, you should definitely implement SSL. SSL requires a certificate on your web server, to validate your identity to your customers. There are several companies that provide SSL certificates. Here are a few:
Some web host providers offer Shared SSL on their servers. This means that the web host owns the SSL certificate, and it is shared with multiple clients on one server. If this option is available to you, the secure URL for your site would look similar to the following examples:
Typically there is no charge for this, but some hosts will charge a small monthly or one-time fee. For information on whether or not this option is available to you, contact your web host provider and ask them for information on Shared SSL.