Subsequent to making the earlier e-reader post I realised that I hadn't the foggiest idea what Caecilia looked like.

Turns out it's a slab serif font, I imagine that's more forgiving in terms of screen rendering than standard serif faces. It can be perused or purchased here on the Linotype site. It's a "proper" font too, released some 20 years ago, rather than one of these new-fangled generics.