As others have reasonably pointed out, file formats are file formats... But when you start tagging your files, commenting on them, linking them semantically to other files, etc. you start to add proprietary "metadata" to those files in whatever service you are using.
So the question really is all about porting this metadata from service to service and that's where the "Hotel California" effect is applicable. Standards can help, but nobody has an incentive to participate as yet.
Unless customers demand this portability and migrate to services that support it, the offerings will continue on their current path...
As others have reasonably pointed out, file formats are file formats... But when you start tagging your files, commenting on them, linking them semantically to other files, etc. you start to add proprietary "metadata" to those files in whatever service you are using. So the question really is all about porting this metadata from service to service and that's where the "Hotel California" effect is applicable. Standards can help, but nobody has an incentive to participate as yet. Unless customers demand this portability and migrate to services that support it, the offerings will continue on their current path...