By Dan Gillmor - Today, I cannot imagine why a parent – or school – would buy any encyclopedia in book form. That's why my only surprise at hearing that Britannica will no longer be printed is that the decision took so long to make.

It's not the only overdue cessation of a print product, of course, but a genuine milestone in the history of shared human knowledge. Yet, as the company is telling journalists, this is not a death knell for the wealth of knowledge it has accumulated. The company has been moving more and more online, and shifting its business model; it will be fascinating to see how that material moves forward in this digital era.

The printed Britannica's days have been numbered for well over a decade, and it's not Wikipedia that foretold its demise. The credit more properly goes to Microsoft's pioneering Encarta, a CD-Rom product the software company launched in the early 1990s and maintained until 2009 in several formats including, late in its life, a web version.

Encarta wasn't as good as Britannica. It didn't have to be. It was good enough to become a useful reference aid to countless people.