I would like to see Prismo implement webmentions. Webmention is a standard for sending mentions across the web. Implementing webmentions would increase interoperability with IndieWeb sites.
When a user posts a link to a blog post, Prismo should send a webmention to that blog. The author of that blog post would receive a notification and could join in the conversation. Comments on Prismo should also trigger webmention sending and blog authors could choose to display these comments on the original blog post (with links back to the Prismo thread).
The IndieWeb wiki has details on how to implement webmentions here.