I may have said this before, but footnotes would be an amazing feature for Less Wrong to have. The main way Less Wrong is trying to improve the world is by providing a forum for high quality discussion. This effectively cashes out a nuanced arguments backed up by evidence that are also well-explained.
Footnotes encourage people to provide evidence for their claims by making it as easy as possible. We do have hyperlinks, but sometimes people will want to refer to offline resources such as book and sometimes people will want to add additional notes about why a resource is valuable or what kind of study it is.
Another advantage of footnotes is that they allow you to provide more nuanced arguments. Often I find myself wanting to provide justification for a point without breaking up the flow of your writing. Having footnotes encourages you to produce content that engages with other perspectives instead of just taking things for granted.
Finally, footnotes lead to clearer articles. They allow you to explain a concept in more detail so that the reader isn't left trying to figure out things themselves. They also allow you to take technical and difficult to understand points out of the main flow so that they don't trip up readers who struggle to follow them.
It is possible to write footnotes yourself, but without the ability to easily skip back and forth between the main text and the footnotes they are very inconvenient for both the reader and the writer. Undoubtedly this feature would be technically complicated, but the benefits that it would offer are significant.