In a move to provide more accurate measurement of users engagement in a Web 2.0 world, Nielsen is now tracking “Total Minutes” and “Total Sessions”. This allows them to present a better picture of what users are experiencing online as users consume more Flash and Ajax applications. It will be interesting to see how this metric effects online advertising, much of which is still sold on a CPM basis.

Nielsen Redefines Site Performance for Web 2.0 via Yahoo!