From their page:
- Page Authority correlates higher than any other metric we measured.
- Social signals, especially Google +1s and Facebook shares are highly correlated.
- Despite Penguin, anchor text correlations remain as strong as ever.
- New correlations were measured for schema.org and structured data usage.
- More data was collected on external links, keywords, and exact match domains.
Really not only are you already doing well, but
your already ahead of the game due to #4 already being a strong focus.
#2 Social networking - I'm not going to get into detail but the premium is going to be a full-on twitter app which integrates many aspect of your network communication and image promotion. So not only will Symbiostock have a sort of combined voice on twitter, but it will funnel down to promoting your site on a few levels.
For those skeptical - this isn't going to be your noisy little blue bird competing for attention - its actually going to make practical use of twitter's API without aggressive promotion.
I'm not touching facebook - I personally think its evil and takes more than it gives - but there is still plenty you can do with it using basic wordpress plugins.