Tika provides outlink extraction features that are not used in Nutch. To be able to use it in Nutch we need Tika to return the rel attr value of each link, which it currently doesn't. There's a patch for Tika 1.1. If that patch is included in Tika and we upgraded to that new version this issue can be worked on. Here's preliminary code that does both Tika and current outlink extraction. This also includes parts of the Boilerpipe code.