Proof point on my comment about SEO Services. Think about how much SEO-Related Infrastructure / Services (link farms, article directories, spinners, cheap cont

Proof point on my comment about SEO Services. Think about how much SEO-Related Infrastructure / Services (link farms, article directories, spinners, cheap content writer services, link spam) were devalued by Penguin/Panda. Social media submission / follower spam is likely next. From a business perspective, I'd value any pure-play SEO service using the assumption that the product offering would need to be totally replaced in under 18 months. Google changes that fast. Now - granted a lot of this was spam and likely should not exist... but there were a lot of legitimate / semi-legit revenue streams for large sites derived off helping new sites navigate the Google Pagerank Algorithm...