Unnatural links and Penguin recovery Cognitive SEO
Link building from Buzzstream
50 reasons a site is penalised – don’t panic it can recover
feedthebot.com has a google webmasters guidelines checker. The http-last-modified test is not one that large sites that rank well in travel seems to use Wotif.com and Hotelclub for example do not use the http-last-modified test.
Backlino – Skyscaper Technique, find content, do it better, reach out to get links from whoever is linking to the content that isnt as good as your new content
Moz.com ranking factors for 2015