I've been playing around a bit lately with a couple of JavaScript libraries that implement includes, or "transcludes". That is to say, with a bit of JavaScript, you can stick parts of other HTML pages into your page – and it's the browser, not the server, that does the fetching work.
That minimizes the load on the server, and potentially allows the browser's cache to help out.
Hinclude came first, offering the basic functionality.
Then purple-include came along, made by the Purple people, unaffiliated with libpurple.
Purple-include builds on the original idea and adds some new features: the ability to include remotely-hosted HTML via a proxy, and the ability to pick and choose what parts of a page to include with XPath. Here's a page of it at work.
I'm not sure if this function really solves a real-world problem, but it's cool. It's part of the same Englebart-inspired project that does purple numbers, which do address an existent need – the need to link to sub-parts of a web page that doesn't have anchor links.
Let's hear your scoffs.
