While we focus on the iPad-Kindle war, another Kindle rival may have quietly eclipsed it.

Barnes & Noble's Nook outsold the Kindle in March, according to DigiTimes research.

DigiTimes researcher Mingchi Kuo based his report on "figures from upstream suppliers as indicating that the nook accounted for 53% of e-book readers shipped to US vendors last month."

DigiTimes attributes Nook's success to its being a newer product and being available in retail stores.

If this report is accurate, it helps explain Amazon's move to start selling Kindles in Target, where people will be able to get hands-on with the products.

It's also another sign that the Kindle is due for a refresh.

In Amazon's last earnings report, it said the Kindle was its best selling product for the quarter.

See Also: 10 Obvious Things Amazon's Next Kindle Will Do To Compete With The iPad