title: How to define custom filter to block spam in Drupal
body: <p>Drupal has a nice <a href="http://drupal.org/project/spam" rel="nofollow">spam module</a> with a lot of features, including defining Custom filters. The filters can be either Plain text or Regular expressions. I am a bit familiar with regexp but not sure how to define regexps in spam module in order to block any occurrences of spam strings like</p>
  
  <p>myblablaviagra.com</p>
  
  <p>or phone numbers like:</p>
  
  <p>091234567</p>
  
  <p>The thing that I am really not sure of is that whether the regex need to be enclosed in '/ /' or something else. Unfortunately I could not find any examples of custom regex filter in action, hence the question.</p>