When traffic is coming to your website or blog, nearly unfettered, it gives you the opportunity to test out a variety of marketing initiatives. However, without that traffic, you're forced to spend money on costly ads before really determining the effectiveness of your offers and uncovering your cost-per acquisition (CPA), two things which are at the core of scaling out any business online.
While most of the links to your site will be added gradually, as people discover your content through search or other ways and link to it, Google understands that you'd like to let others know about the hard work you've put into your content. Effectively promoting your new content will lead to faster discovery by those who are interested in the same subject. As with most points covered in this document, taking these recommendations to an extreme could actually harm the reputation of your site.
The truth? Today, rising above the noise and achieving any semblance of visibility has become a monumental undertaking. While we might prevail at searching, we fail at being found. How are we supposed to get notice while swimming in a sea of misinformation and disinformation? We've become immersed in this guru gauntlet where one expert after another is attempting to teach us how we can get the proverbial word out about our businesses and achieve visibility to drive more leads and sales, but we all still seem to be lost.
When would this be useful? If your site has a blog with public commenting turned on, links within those comments could pass your reputation to pages that you may not be comfortable vouching for. Blog comment areas on pages are highly susceptible to comment spam. Nofollowing these user-added links ensures that you're not giving your page's hard-earned reputation to a spammy site.