Google’s baptism-of-fire A/B testing continues this month with yet more experimentation with THAT navigation bar. They’re experimenting with the idea of hiding the cross-service navigation - a site element that has been used, loved, and sometimes abused for the promotion of new services most people never knew they needed.
Stacked navigation is something that we have been brave enough to implement on a number of projects including our responsive Arsenal.com designs for tablet and mobile, often without the luxury of A/B testing. Our overall impression from users is that, used appropriately, some economy with navigation can be an elegant solution to an exponential problem.
Google’s access to significant data on user behaviours with this bar sets them in good form for experimenting with this, but it’s brave all the same. On a similar note, I’m still waiting for multiple sign-in to be implemented everywhere.