Floating Share Widget based on Views, Posts, Likes, etc.

I've found that the "share buttons" at the bottom of the Xenforo pages (and vBulletin, coming from there) go largely ignored and are rarely used, let alone seen. A lot of great content just seems to go "unshared" because these icons always seem to be an afterthought, appearing innoucuously at the bottom of the page in small print.

It would be nice to have an Add-On that floats share buttons to the side of forum posts, perhaps appearing when threads reach a certain threshold of comments, views, or likes.

I've attached a screen shot.

Notice the share on the left side. This box would "float" with the page as it is scrolled.
This definitely would encourage more social sharing on website's that are creating great content, versus the standard links at the bottom of the page which are ineffective.

Preferably, the share buttons should only show when a certain thread meets a specified number of views, likes, or comments.

Flare offers a plugin that only works on Wordpress sites or static HTML sites ... doesn't seem to float for forum installations.

How difficult would this add-on be to build? This is definitely something I'd pay for.