title: Email address validation Vs sending mail for activation?
body: <p>Well it looks like stupid Question but I recently came across a scenario where I have to decide which way should I do this?</p>
  
  <p>Let me explain my case.
  Email address are used in many other cases apart from just Signup and sending mails e.g. service must be allowed if the request came from the mail, it was sent to not if the mail is forwarded to another address; I assume you got the point.</p>
  
  <p>there are two approaches ( as far as I was able to classify, let me know if there are more) viz.</p>
  
  <ol>
  <li><p>while signup, system will send a mail and user has to click on link ( inside mail) in order to activate its account.
  In just above case; 
  First we are verifying that person who is signing Up owns the email address, Also he wants to use system.
  So, here we just check that email address provided has '@' in it and we try to send a mail to it. If it is fake it will bounce.</p></li>
  <li><p>Use Regular expression in order to validate email address with certain formats which are in use like person cannot have email address with '! { } &amp; ^ " many more characters, Ultimately It will reduce the mail bouncing as per me.</p></li>
  </ol>
  
  <p>I tried to explain both the cases above;
  Hereby I ask you which way you think is best?</p>
  
  <p>OR </p>
  
  <p>There is another way apart from above which is much better?</p>