Tracking Scroll Depth with jQuery and Google Analytics
ravelrumba.com
ravelrumba.com
What might make more sense is tracking who scrolled down to the end of the .blog-post div, to the end of the .comments div, and to the end of the footer. Or whatever makes sense for the content on your page(s).
Btw, tracking scroll points for specific DOM elements is one of the plugin options, so for instance you could track the end of the .comments div as you mentioned.
Some other solutions I like http://www.savio.no/blogg/a/114/tracking-content-scrollers-s...
http://cutroni.com/blog/2012/02/21/advanced-content-tracking...
Yet another reason to use ScriptNo (Chrome).