From the beginning of the internet the protocol used to communicate has been HTTP(Hypertext transfer protocol). Unfortunately HTTP allows data to be viewed in plain text when sent across the wire. This means that websites are vulnerable to attacks which intercept and manipulate data. One type of attack is called Man in the Middle where two parties are having their communication intercepted, stolen or altered. Another kind of attack is content injection. This means malicious code, ads or other content can make its way onto your website without your consent.