I suggest considering the inclusion of open microblogging, which could be viewed as a precursor in this context. Although a decent project, open microblogging attained a substantial prominence in the open social web landscape, potentially due to effective lobbying efforts. There was initially a drive to rival Facebook and its application ecosystem, encompassing open social. However, these endeavors seemed to be relegated due to the strong promotion of open microblogging. To this day, the lack of a robust open social graph and a viable competitor to Facebook is still apparent.
It could be argued that OStatus may have inadvertently delayed our progress by around a decade. However, I believe it was the combined influence of Open Microblogging and an emphasis on micro blogging in general that have eclipsed other use cases in the open social web.