An anonymous reader writes: Glyn Moody writes at The H that Google's Nexus 7 tablet seems to be in a good position to shake up the market and pave the way for a serious threat to the iPad. That said, he's worried about the potential downsides to a market full of mostly 'open' devices: 'Such customised systems are likely to be as locked down as they can be – the last thing either manufacturers or companies want is for users to start fiddling with the settings or installing their own software. As a result, the apps that run on such systems are likely to be closed source, since that's the way vertical markets tend to work. Such systems will also expose a persistent problem with the open source development methodology. While big and general projects find it relatively easy to attract interested developers, smaller, more targeted solutions tend not to thrive as free software.'