This may be a bit of a nit-picker question but in recent Panda discussions and general SEO posts, we've discussed the fact that SE are now looking at how quickly the user hits the 'back' button when they click on a SERP entry.
However I've noticed that when I do that using Firefox 8.0, the SERPs page is cached and thus there's no re-load from the search engine's server. So how do they know I've hit the back button?
Is it more that they look at how quickly you click on another entry in the SERPs or go to the next page?
Sorry if this sounds a bit nit-picky but I'm just trying to get my head around the whole Panda thing (I realise this is just part of it) and what the search engines are doing or looking for it terms of user experience etc.