[issybird]

I think the phrase "locked into a system" refers to content, not devices. It's a distinction that is less meaningful now that the eink reader market has contracted than it used to be. Just the same, DRM content from Amazon can only be read on Kindles and DRM content from B&N can only be read on Nooks. So to the extent that you purchase content from the store linked to your proprietary device, with both Amazon and B&N you are locked into the system.

With Kobo, however, content from the Kobo store can be read on any eink device that reads epubs, including Nooks and Pocketbooks, and hence you're not locked into a system. The phrase has nothing to do with non-DRM content that can be loaded onto any device, converted if necessary, without recourse to Alf for those with legal or moral issues. But the "locked into a system" aspect is why stripping is Scripture at the Church of MobileRead. Amazon's not going anywhere, but that might not hold true for other purveyors as we've all seen. Let's not forget Mobipocket at that.