Today I read with delight that the nofollow attribute of the href element has been added to HTML 5! Something I was adamant about from the day it was proposed by the Search Engines. Search engines shouldn't be telling webmasters/SEOs how to use HTML attributes. This means that Google's guidelines now conflict, to some degree, with the future HTML standard since they only seem to be talking about "paid" links which is just vague enough as to be less than useful to figure it out. IMO, like the paid blogging fiasco whom you have to wonder how could they be so F'in dumb as to think the FTC doesn't step in. They are all a bunch of johnny come lately's who don't understand this shit runs on protocols and standards not search engine guidelines and edicts from the spam crusaders... been there and done that... "I'm the original" and got the lonely guy Tshirt to prove it!
What are link relations?
Regular links (<a href>) simply point to another page. Link relations are a way to explain why you're pointing to another page. They finish the sentence "I'm pointing to this other page because..."
Bold is my emphasis. Quote from The Road To HTML 5 Link Relations by Mark Pilgrim, Google
This should clean up any doubts as to what should be viewed as a "paid" in the Google Guidelines. It is now up to the webmaster to decide what their intent is not the Google guidelines. Google may choose to interpret and take any action they want to if that is what they deem necessary to protect the integrity of their resource (that is always the elephant in the room), however, that shouldn't include the Google bottom line which in these matters is the elephant in the other corner.
"indicates that the link is not endorsed by the original author or publisher of the page, or that the link to the referenced document was included primarily because of a commercial relationship between people affiliated with the two pages." Bold and red is my emphasis. Quote from whatwg.org
The above quote provides a webmaster with the means to indicate transparent intent of the link because that is what the rel attribute is supposed to do for Search Engines. It could become the law if the FTC who, IMO, could use this to indicate commercial endorsements much like financial analysts disclose their personal and company holdings or that their firm provides services to the company. This could be done by using the page properties function in the browser.
A Not For Profit Organization with commercial relationships may not be "affiiliated people" and the transaction may not be the primary reason for the link. For instance a SEO directory should use nofollow if it's all about advertising and the relationship is all about commercial endeavor of one or the other parties. However, even an Organization that doesn't vetted the members should consider nofollow otherwise they could be seen to be endorsing the landing location/page and definitely the person adding the is. Whereas SeoPros through adoption of the OSEOP mandate has a mandate that states first and foremost we're there for consumers. Since the review for the directory is not based on a commercial transaction but rather the Members suitability or a "bonafide endorsement" the $25 review fee isn't the primary concern.