The World Bank is currently working with a few countries that are planning for the procurement of lots of digital learning materials. In some cases, these are billed as 'e-textbooks', replacing in part existing paper-based materials; in other cases, these are meant to complement existing curricular materials. In pretty much all cases, this is happening as a result of past, on-going or upcoming large scale procurements of lots of ICT equipment. Once you have your schools connected and lots of devices (PCs, laptops, tablets) in the hands of teachers and students, it can be rather useful to have educational content that runs on whatever gadgets you have introduced into to help aid and support teaching and learning. In this regard, we have been pleased to note fewer countries pursuing one of the prominent worst practices in ICT use in education that we identified a few years ago: "Think about educational content only after you have rolled out your hardware."
At least initially, many education authorities in middle- and low-income countries seem to approach the large-scale procurement of digital learning materials in much the same way that they viewed purchases of textbooks in the past. On its face, this is quite natural: If you have tried and tested systems in place to buy textbooks, why not use them to buy 'e-textbooks' as well? (We'll leave aside for a moment questions about whether such systems to procure textbooks actually worked well -- that's another discussion!) As with many things that have to do with technology in some way, things become a little more complicated the more experience you have wrestling with them.