Adopting a single protocol by the masses is something that rarely works. It's much easier to gain critical mass if a server platform (like Wordpress) included an annotation module as part of its default modules, so that it appeared at many websites as soon as they update to the latest version. Then, it could catch on as a popular feature, and other platforms would start to build their own implementations, making it more visible and gaining traction all over the web.
(That Wordpress module could very well be the hypothes.is software, if they're compatible. But it really needs to be adopted server-side by a popular service to gain traction).
