Hi … I’m afraid this isn’t supported by the plugin as the Follow button doesn’t have the same content or format as the contact links that WordPress supports and that WP Biographia adds to; these are basically just simply URL links, with optional icons.
You could, in theory, generate the HTML and Javascript code that makes up a Twitter Follow button by using the generator on Twitter’s web site (https://twitter.com/about/resources/buttons#follow) and then write some code that hooks into WP Biographia’s wp_biographia_links filter so append the button to the list of contact links. But this is in theory only; it would mean writing some PHP code and you would probably have to also add some custom CSS to make sure the styling of the button aligns with your theme.
-Gary
