In-house and freelance SEO based in Boston, MA. Able to assist in technical site optimization, link acquisition, keyword research, and Google penalty removal.
Google's official stance is that they are "roughly equivalent" and recommends to do what is technically simpler to implement (source: https://www.youtube.com/watch?v=_MswMYk05tk).
With that said, I'd recommend a directory over a subdomain.
Doing this consolidates signals to a single domain, which should then theoretically build more authority for all pages off of that single domain. This consolidation of authority results in rank increases, which have been documented here: http://moz.com/community/q/moz-s-official-stance-on-subdomain-vs-subfolder-does-it-need-updating. A subdomain would split signals from the blog and the rest of the root domain content.
So while Google "says" they're roughly equivalent, SEOs have seen tangible evidence that sticking to a single domain can be beneficial.
If you're able to go with www.iconery.com/editorial/, I'd choose that.
Hope this helps!
Having read a few of Brian's tactics, I'm suspicious as to whether or not he submitted this question himself! :)
But no, this guide is not enough. This is a *tactic* that can be useful for earning links, but it is not a silver bullet solution. Link building is one of the most creative aspects of SEO and a good SEO should use a number of different tactics to earn high quality links.
If you'd like to see a list a link building tactics, I recommend reading Jon Cooper's guide here: pointblankseo.com/link-building-strategies.
Further, when determining quality, I recommend you consider not just the prorietary "SEO value" of the link (e.g. Domain Authority, TrustFlow, etc.) but also the topical relevancy and authority of the site (i.e. what is the site you're hoping to earn a link from actually about?).
Hope this helps!