We do a fair number of rebuilds for existing websites. Typically it means that we copy the website content over from one site to another. Often times I'll come across pages that have an email address as part of the text on the page. Those same individuals often wonder why they are getting a ton of spam emails to their account. Often times they get on those spam lists because a crawler that does nothing but look for email addresses on web pages is grabbing that email address and once they have it your going to get spammed and possible get spammed a lot.
The solution to this is either to obfuscate the email address on the website using a little code so that the spam bot won't recognize it as an email address or put a form on the page to replace the email address, which will hide that email address from the public. Both of these things are very easy to do on a concrete5, Wordpress, Joomla or Drupal website.