Posted by larry.kimRand Fishkin posted another brilliant Whiteboard Friday last week on the topic of optimizing for RankBrain. In it, he explained how RankBrain helps Google select and prioritize signals it uses for ranking.One of the most important signals Google takes into account is user engagement. As Rand noted, engagement is a "very, very important signal."Engagement is a huge but often ignored opportunity. That's why I've been a bit obsessed with improving engagement metrics.My theory has been that R...