A standalone parser written in C is a great asset. Pretty much any language worth mentioning has C bindings, so they are now just a bindings implementation away

A standalone parser written in C is a great asset. Pretty much any language worth mentioning has C bindings, so they are now just a bindings implementation away from having a reasonably fast (the fact that performance was a non-goal notwithstanding), standards compliant HTML parser. This is an improvement over the status-quo where most languages have bindings to lxml which is fast but has made-up error handling and a tendency to deal poorly with quite a lot of content, and some languages have slow, native implementations of the HTML standard parsing algorithm (I wrote much of Python's html5lib so I am aware both that it is slow and that it is non-trivial to speed up). Compared to Gecko and WebKit, this gives you just the parser, which is significantly simpler than the whole engine and all you want for many applications.