For TRAILING and (especially!) LEADING positions, we need to decide on metrics to measure user impact, then track and follow up as needed.

For example:
* Total tabs opened
* Fraction of keyboard shortcut vs. button use
* Frequency of manually focusing first/last tab
* Number of tabs scrubbed over in strip (this is a proxy for "user had to keep moving mouse back and forth a lot")

Mark, I'm sticking this on your plate to either decide what metrics we'd need to make good decisions, or triage to someone who can decide this.  (I don't feel like I have a good sense here.)