On the web, SSL tries to do two things:
Encrypt and verify the integrity of traffic between the browser and the server.
Verify that the browser is talking to the correct server. In practice, this usually means verifying that the owner of the domain and the owner of the server are the same entity. This helps prevent man-in-the-middle attacks. Without it there’s no guarantee that you’re encrypting traffic to the right recipient.
It’s more secure. In particular, it significantly reduces your risk of being exposed to a man-in-the-middle attack.
Users correctly feel more comfortable sharing their payment information on pages visibly served over SSL. Your conversion rate is likely to be higher if your pages are served over SSL too.
How can I tell if a web page is secured?
There are two general indications of a secured web page:
1) Check the web page URL
You should also check the URL (website address) to see if the site is secure. Secure web sites will start with https:// instead of just http://. For general web browsing, URLs beginning with http:// are fine, but when transmitting personal or confidential information, you want to be sure the site begins with https://.
2) Check for the "Lock" icon
THE LOCK ICON IS NOT JUST A PICTURE! In addition to the warning messages that many browsers use when you enter or leave secure sites, most browsers also display a security icon, usually a small locked padlock, when you are on a secure web site.