Update: I had not noticed until it was pointed out to me in the comments that the article I was reporting on was a year old. It was shown in Zite as a recent article (probably because of the “March” dateline without a year in the blog posting format). My eyes slid right over the “2011” in the subject line. I should have done more research, but I was in a hurry to post. I apologize for misreading the date.
In fact, there was a more recent article from July stating that, due to friction with Amazon’s education representatives, the Unquiet Library would not be using the Kindle any longer, and was moving to Barnes & Noble’s Nooks in the future. The Unquiet Library was using five Kindles per account, as consumer accounts are allowed to use up to six, but Amazon now requires libraries, including K12 and school libraries, to use a single Kindle per account.
At the time the article was written, Amazon didn’t offer any other content management systems other than a subscription to Overdrive—not financially feasible for school libraries. As stated in the comments below, the Unquiet Library is now using Nooks (though I couldn’t find any articles about how it is using them in searching the site).
I still stand by my comments in the last paragraph of my post. The article said: