Hey Matt, not sure I agree with the logic there.
The only important metrics here are quality and relevance. If you contribute in a quality discussion and bring value, then you could do this all day long. Likewise, if you build a best of class resource or provide the best answer, you are going to see people linking to it from forums, blog comments etc.
Quality, is a great way to put the breaks on and there is only so many quality forum interactions you can manage in one day. Likewise, there are only so many quality discussions in any one given day.
The risk factors here is if you get silly with anchor text etc. Just link natural, the URL is likely best, forget anchor text, just provide the reference. They are nofollowed so effectively not part of the link graph anyhow so in my experience, you can fill your boots here, but just mind the quality and relevance.
Have you a single example where contributing to high quality forum discussions would provide a negligible impact on traffic? Are we not swaying into negative SEO paranoia here?
Re: Everything is okay in moderation, but as a link building strategy?
This is not a link building strategy, this is an exposure, branding and referral traffic exercise. Sure, there are links that may in turn drive traffic, but it will not impact your rank in any meaningful way (unless someone sees the discussion, reads your resource and in turn links to it so... another reason to focus on relevant, high quality, high traffic sources where you are further telling the world about your great resource you linked to).
Nobody should be scared of contributing to a discussion in a meaningful way and dropping a link if it adds further value. If you try to add some SEO to this, start trying to use targeted anchor text, start creating discussions and linking out from them or start dropping the links in irrelevant places well, I would still venture that will do no harm, but it is going to be a big fat waste of your time but still, then you are trying to manipulate things and you deserve anything you have coming.