The ProspectEye tracker is simply a small Javascript snippet that you put on your site. Once it is activated (that is, inserted into the markup of your site) it will track all visitors coming in and relay that information to ProspectEye's service.
Here's an example of what the code snippet looks like:
<script type="text/javascript">
var psSite = "xxx"; var peJsHost = (("https:" == document.location.protocol) ? "https://" : "http://");
document.write(unescape("%3Cscript src='" + peJsHost + "tr.prospecteye.com/track.js' type='text/javascript'%3E%3C/script%3E"));
</script>