text: As I said in my reply, there are at least six points of distinction between Bitacle and the legitimate search engines:
  Lack of Opt Out – Bitacle completely ignores robots.txt files, disregards meta tags and offers no means to opt out of the site. Though Bitacle claims there isn’t any “norm that forces (them) to obey the robots.txt“, the presence of an opt out mechanism was critical to Google, and other search engines, in having their cache judged to be fair use (PDF, see pages 20 and 21).*
  Displays Full Content – Though major search engines cache Web pages, they do not display the full content of the sites they index on their own result pages. They display, at the most, small snippets of content. Also, search engine caches display the content in the original context, capturing all images, licenses and attribution, Bitacle merely scrapes the content and formats it for their own site.
  Destination, Not Direction – Major search engines exist to direct users to the sites they want to see, not to be end destinations. Bitacle’s “aggregates” feature not only displays the full content of every post, but also offers a Digg feature and a comment form. Users have almost no motivation to leave Bitacle’s version and visit the original site. These are clear signs that Bitacle’s goal is not to direct users to the sites they scrape, but to keep the traffic (and money) for themselves. This means that Bitacle’s use is not transformative (where the use of the copy is different than the original intent) and thus almost certainly not fair use (See above PDF pages 14-16)