For our client: We rolled out a successful implementation of rel="author" for the three in-house content writers the company had. The client had over 300+ articles made by these content writers over the years and it was possible to implement rel="author" for all the aged articles. I advise anyone who has a large section of content to do so as it will only benefit the website. We were also in the process of rolling out further schema markup to the site's course content as it only has a benefit for CTR.
Remember when you used to rely solely on search engines for traffic? Remember when you worked on SEO and lived and died by your placement in Google? Were you #1? Assured success. Well, okay, maybe not assured. Success only came if the keywords were relevant to your site users, but it was the only real roadmap to generating site traffic and revenue.