Do people actually add webpages to their home screen?
Just looked at my Apache Server logs to see if there was a difference in the user agent string when a page is called by an Add to Home app vs directly from Safari.

And indeed there is a difference.

The web app is calling itself:


  "Mozilla/5.0 (iPhone; CPU iPhone OS 6_1_4 like Mac OS X)
  AppleWebKit/536.26 (KHTML, like Gecko) Mobile/10B350"


While straight up Mobile Safari identifies itself as:


  Mozilla/5.0 (iPhone; CPU iPhone OS 6_1_4 like Mac OS X)
  AppleWebKit/536.26 (KHTML, like Gecko) Version/6.0 Mobile/10B350
  Safari/8536.25


This feature is very simple to implement using Matteo Spinelli's "Add To Home Screen" script.  You could deploy it on your site and the look at your server logs and see if anyone is actually using it.

http://cubiq.org/add-to-home-screen