IanTurner - 1:52 pm on Sep 14, 2012 (gmt 0)
Having read the Adjusted bounce rate link - I'm not sure how it would be of use.
Someone whois is price matching products is going to visit your site for only a short time and bounce if your price isn't good enough - if they find exactly what they want (i.e. the product with the price) on the page they land on - visitor has bounced but they found exactly what they wanted, page was useful to the visitor.
If they don't find the product and the price on the page they land on - but maybe find a list of product variants they are then going to click to the next page to find the exact product and price. In this case you have more user engagement, but the landing page was actually less useful for the visitor.
Someone who stays on your page a long time and bounces may still only have been price matching the products, but did it by opening all the SERPs in new tabs and then going through them to find the prices (that is what I often do when looking for the best deal and may keep some of them open while I make my purchase just in case there are catches like high delivery charges, too many personal details requested in the checkout and such like)
I'm not sure long bounce, short bounce or number of pages visited is actually an indicator, for an ecommerce site, of good user engagement at all.
You can put together a similar argument for some informational sites too, espcially if thy are providing specific answers - if the user has to click through to find what they want from the landing page then the landing page is wrong, the user engagement created by the user having to click through to a secondary page to find what they wanted is actually wasting the users time whereas for the user who finds what they want in a second on the landing page and then closes the page the landing page was spot on and the user got what they wanted with the minimum of fuss.
This is what I find really difficult with User Metrics of every kind - it is difficult to decide what is good and if you make your decision as to what is good and it doesn't match Google's you're not going to be in good from a traffic point of view.