Comment on WordPress Social Network Theme by Mark.

WordPress Promotion Theme That above mentioned site if you study it is a testament to what can be done with social media engineering.
The content itself is nothing spectacular, similarly, the look is nothing to write home about; yet, it is well thought out in terms of design – to get you to share it on Facebook to comment on Facebook which can lead to exponential growth if the content has emotional appeal.

I personally think Facebook is the Google of Social Media all otehr buttons pale in comparison. If that one button alone was easy to see and click then that alone could give you enough social signals (the links of today) to propel you to another level of organic traffic. I rarely get meaningful traffic from Twitter or others, maybe an argument can me made that Google + is the Bing of Social Media.

I like the CSS box around the FB share as this makes it light and mobile friendly yet does enough to attract attention.
You are correct to be cognizant of SEO considerations. You do not want your juice (whatever they call PR these days) flowing just anywhere, and yes Google going crazy with performance testing but it is a company run by academics and engineers, therefore, that does not surprises me. They are looking for measures to quantify quality on site and off site.

So if you did add some flexibility in social media and sharing (really FB is the most important). That would be greatly appreciated. In the mean time I may play around with CSS and plugins, or cute images (like a cat sharing with a dog) To test the affects.