I'm not a fan of infinite scroll in the main, but there are use cases for it. I've often thought search results would be a good candidate. The don't suffer from the need to provide user feedback on progress of completion. I also think it provides Google with more ad opportunites including placing them within the infinite scroll at some interval, and, of course, the highly prized sticky ad ;) [edit - wanted to add that it would also lessen the blow of being on p2 ... in fact I would expect search users to frequently get deeper into the results yielding an improved feedback loop]
I've been using a userscript [1] for the past year that adds the feature to search results and the like. Huge improvement, and with a little custom CSS styling the additional pages are appended more seamlessly.
The feature I appreciate about this particular userscript is it's clear where the page breaks are, and adds links to each newly appended page, allowing the user to link directly to them - which would be useful to see in more infinite scroll implementations, and seen used in the main HN link.
