I have a web page loaded up in the browser (i.e. its DOM and element positioning are both accessible to me) and I want to find the block element (or a sorted list of these elements), which likely contains the most content (as in a continuous block of text). The goal is to exclude things like menus, headers, footers and such.
There's a simple technique to do this,based on analysing how "noisy" HTML is, i.e., what is the ratio of markup to displayed text through an html page. The Easy Way to Extract Useful Text from Arbitrary HTML describes this tex, giving some python code to illustrate.
Cf. also the HTML::ContentExtractor Perl module, which implements this idea. It would make sense to clean the html first, if you wanted to use this, using beautifulsoup.