Kevin offers an excellent invitation to have a strategy and metrics for social media sourcing. Each one of the social media sources offers a different front end to the candidate experience. Each social media has a user base of potential candidates with similarities and differences. The use of exceptional HR analytics can help identify the meaningful differences.
To optimize social media it must tracked by source through various stages and filters such as number of candidates who engaged in the application process by source, number of hires by source and quality of hire by source.
Sources can vary significantly in overall yield. That means more objective understanding of the value stream is essential. An example of a firm doing it well is here. This client case study has lessons to leverage.