title: Client-side "Feature Tour" (tutorial/instructional) overlay system?
body: <p>Is there a system/framework in existence which focuses on providing tutorial / help like overlays in the browser?</p>
  
  <p>Example: You have a webapp which requires a certain level of instruction to the user. In this instruction process you wish to "highlight" (e.g. arrow, colour shading, pulsing border, etc) a certain element on the page, with an accompanied message.</p>
  
  <p>This would be a true overlay, so it would function only in absolute positioning, and not interfere with the existing layout.</p>
  
  <p>I'm looking for an existing solution, before I consider rolling my own.</p>