It's clear that there were increasing numbers of sub-industries, and players in those sub-industries, over time. SEO in 2011 certainly wasn't nascent, but it w

It's clear that there were increasing numbers of sub-industries, and players in those sub-industries, over time. SEO in 2011 certainly wasn't nascent, but it was a bit of a black art, and not an especially large sector. I don't think there were (m)any that were offering exclusively SEO products -- from memory it was more of a bundled / add-on offering for other services.