The progressive adoption of static site generators (or SSGs, like Jekyll or Nikola) for blogs has resulted in many sites dropping comments (i.e. dynamic content), which is detrimental to the use of blogs as a medium for thoughtful and diverse conversation. To avoid this loss of functionalty, other static sites have instead opted for centralized, closed and mutually incompatible platforms (like Disqus or IntenseDebate) to host their comments. However this adds to the recentralization trend that is plaguing the Internet in the latest years.
There are Free Software alternatives (like Isso) that allow people to run their own comment servers. However, they still keep the comments of each site as a closed silo. In contrast, some months ago Enkidu (Las Indias) started the development of the WP-GNU social WordPress plugin, which uses conversations in GNU social (a federated microblogging system) as a replacement for classic site-only comments.