If you are using an SSL certificate on your Drupal 7 website you may have an issue whereby you can access your site via both the HTTP and HTTPS url. This can cause problems for your website with search engines as it is creating duplicates of your pages. You will need to redirect your HTTP url to HTTPS.
Why should your website use HTTPS? HTTPS is most commonly used where sensitive information is sent to a website and if that information were to be intercepted it would be a problem for the user. This information is typically one of the following: