What impact do affiliate links have on SEO

[Zippy-Bungle]

We commonly reference engineering standards on our site (because half our products are known and searched for by those standard names) and have just signed up as an affiliate to an organisation that sell the standards. Which seems a nice match

We're going through and making sure all are no follow now because that seems the general advice - but should we be doing anything else?

Yoast says you should mask affiliate links - https://yoast.com/affiliate-links-and-seo/ - but that was from 2010. Matt Cutts is fairly clear on nonfollow - http://www.webpronews.com/heres-what-googles-matt-cutts-says-about-affiliate-links-and-nofollow-2012-06 - but not on whether it affects SERPS

Does it? And what is the best way to handle it?

This is a typical example of a page where we would have an affiliate link or two. http://www.oakleysteel.co.uk/fake-mill-certificates-en10168

[TomRayner]

Just make sure you no follow them.  If the links were do follow it could be seen as a paid link scheme - I know that sounds quite contrived, but that is how Google might (and has) viewed affiliate links that pass link equity in the past.  They are, in effect, paid links that may help improve organic visibility.

You don't want to risk being a part of that "link scheme", so make sure you no follow your links.  It does seem quite absurd I know and you'd think that common sense would prevail if someone was using affiliate links and wasn't aware of the SEO ramifications, but it's better to be safe than sorry.