title: Emacs org-mode: How to tag entries for viewing a timeline without having them show up in the agenda view?
body: <p>I manage multiple bioinformatic projects with an org mode file for each project containing TODO items, meeting notes and logging of work flows and data transformations.  All my files are collected for an agenda view by customizing <code>org-agenda-files</code>.  The work flows are ordered logically as itemized or ordered lists in the org files and time-stamped as I start them.  It often happens that a step needs to be repeated as input data changes or an error is detected.  So a logical step might have activities with multiple time stamps.  As projects may last many months, I have a need to both review a project logically and chronologically.</p>
  
  <p>The org-mode timeline view (<code>C-c a L</code>) apparently works only with items with 'active' timestamps, i.e. '&lt;2013-03-20>'.  If I use these to timestamp activities, they show up on the agenda view as scheduled activities with a repeater if the dates are in the past.  Is there a way to timestamp activities for a timeline view without having them show up in the agenda view?</p>