title: how to generate unsubscribe link for newsletter?
body: <p>I want to write a newsletter with php. but i have a question: how can i generate a code for unsubscribe. In fact i want a unique code for each subscriber. for example in '<a href="http://net.tutsplus.com/" rel="noreferrer">http://net.tutsplus.com/</a>' you can see something like this:'<a href="http://tutsplus.us1.list-manage.com/profile?u=0154weg635df2fdwied2541cbed&amp;id=c5652sdfre7&amp;e=8758563dfgde" rel="noreferrer">http://tutsplus.us1.list-manage.com/profile?u=0154weg635df2fdwied2541cbed&amp;id=c5652sdfre7&amp;e=8758563dfgde</a>'.
  and another question is that this code should be saved in data base or no?(because i think if it's unique for each person, it's not necessary to generate every time whiling send newsletters). any idea?</p>