Google Analytics is a great resource for many webmasters to make smarter SEO decisions. Just be careful that you aren't blindly following the data without understanding its limitation. A big limitation is the constant erosion of inbound data to GA due to privacy, security & technology issues.
We just finished running a test and found Reddit traffic was under-reported by 384% (of course ymmv greatly depending on site/industry). This is because many redditors use the mobile app which didn't send good data to GA. Once we adjusted the reports we were able to better correlate social success with SEO boosts.
To be clear I'm not saying saying social is the simple secret to SEO rankings or that GA is a bad product. I'm saying that GA can be more valuable if we remember its limitations. Making adjustments can empower us to make smarter SEO decisions. Some of those decisions might be to utilize social as part of a more holistic approach to online marketing. From my experience going viral on social can generate many strong ripples that indirectly boost multiple SEO factors.
To recap: GA not perfect, social is useful, & mobile apps can hide analytics.