There has been an interesting discussion about Glow's use of Microsoft's SharePoint technology (SharePoint is the technology behind Glow). Some have argued that SharePoint is not a good platform while others have pointed out the importance of having a stable environment on which to build Glow.
I see both arguments. My limited use of SharePoint doesn't fill me with excitement in the same way that some Web 2 technologies do - but I appreciate that Glow needs to be built on firm foundations (even if they are a little bland).
My real worry about Glow isn't so much the underlying technology but the danger that it becomes a sort of "pretend internet" - with so many restrictions on what young people can do that they can't wait to ditch it the second they walk out the school gates.