A. Due to readability surveys, we standardized on Arial Black font 13 for it's clear font readability. Changed from Verdana.
B. Added a link every 800 words or so, for those with comments, to a google + hangout community. Seems that we were missing the feedback along the first four chapters and only invited folks feedback at very end.
Have a looksie (1st Link) and perhaps this might engender a few ideas for Your efforts.
And then we have the Ebook4Good edition which comes with Hangout support here http://bit.ly/SocRespEbook2013
Please consider joining our Google + community for weekly Hangouts4Good http://bit.ly/Ebooks4Good