title: MailChimp API, Groups, Segments, and Lists
body: <p>I have a few questions about MailChimp and am looking for a "best practices" answer from someone who knows better than I do. I have several hundred subscribers in a specific list on MailChimp. What I want to do is essentially "classify" them into different groups or segments (I don't know which) based on match calculations like (purchased between 1 and 4 weeks ago, 5-10 weeks ago, etc). </p>
  
  <p>We would like to create specific email campaigns and then blast the subscribers based on the math. I am not sure whether I should use "Groups" or "Segments". We are wanting to run a weekly chron job to reclassify everyone. So we would like to first clear (not delete segments or groups or unsubsribe users) the group or segment and then start looping through our user base and do API calls to reclassify them where we need them to be. </p>
  
  <p>Can anyone help me understand this? I have read the KB (<a href="http://kb.mailchimp.com/lists/groups-and-segments/about-segments-and-groups" rel="nofollow">http://kb.mailchimp.com/lists/groups-and-segments/about-segments-and-groups</a>) but I am still not clear on how I should approach this (groups vs. segments I think). </p>
  
  <p>Any guidance would be appreciated.</p>