How to know email address from which link is clicked?

I am doing one job portal project website for my study. I am sending mail to the jobseeker for job matching. This email is sent based on some criteria matched. This criteria is matched to database with their information. And 开发者_如何学运维I am sending some links with email text. Now there will be one or more than one company matched for same jobseeker. So for each company there will be one link in the email text. And this email can be sent to more than one jobseeker.And for everybody who will get this email, when he/she will click on that apply link withing email there will be same webpage to open but for all pages there will be different details so how can we come to know the details of that jobseeker like email address from which the link is clicked or any other way to open the page according to jobseeker ?

my code for link is

string html3=
        "<FONT SIZE='4'>" + "<a href='" + webaddress + "' >" + "Apply Now" + "</a></Font>";

The only way is to customize the link for each emailaddress you send your mail to.

I'd never ever click an URL again if websites were able to read information from my email client.