This is another player in the game of (pre)rendering the page of the link that you’re about to click on before you click it. The point of which is to get a performance boost for extremely little effort. You’re putting the browser to work getting that next page ready for, say, that half a second between where you hover a link and when you click it, when otherwise the browser wouldn’t have been doing anything.
Instant.page is another player, and I’ve been sufficiently convinced by its methodology to the extent that I run it here on this site right now. I don’t really know the difference between the two. And they aren’t the only players either. Google has quicklink and there’s guess-js for really exotic preloading.
It’s a bit of a pity that Safari and Firefox don’t support
<link rel="prerender">, as it really seems to me the absolute easiest way to pull this off would be to drop that on the page where, on
mouseover of a link, it points to the
href of that link.