To me RSS is exactly that. I don't see the advantage of converting an HTML to RDF because it would cover the entire spectrum. All the semantics might be lost. RSS is the smallest common denominator. If you agree somehow, you might be interested in that tool [0], it converts HTML to RSS using pattern matching.
Sorry, RSS was probably a bad example. I meant that I could have One Interface to Rule Them All, seamless collaboration between similar tools (e.g. viewing repositories on Github and Gitlab in a single application, or ordering a few items from a few different sites in a single place). I think the problem today is that data between websites is disjointed and not interoperable with other sites; my solution would be to build a tool that generates a kind of formula for conversion from multiple sites, such as Github and Gitlab, to a standard format, which can then be consumed by an application. Data and features wouldn't be mapped one-to-one, which is probably one of the larger problems.
The tool looks fantastic though, thanks for sharing.
I did not know this one. The difference is that the first one extracts the feeds automatically, the second one not. Here the user has to define everything.
[0] https://github.com/damoeb/rss-proxy