1. The user can re-download from Instapaper's servers.
2. It goes against the spirit of Apple's policy here, which is not to backup to iCloud what ca be re-downloaded (see 1)
3. The user might have lots of content stored and again due to 1, those don't need to be backed up to iCloud. And really Instapaper actually has a small version of the problem. What is critical is applications that has huge amounts of data like offline maps and wikipedia. Those can be re-downloaded from their servers yet most definitely should not be backed up to iCloud due to time and cost.
2. It goes against the spirit of Apple's policy here, which is not to backup to iCloud what ca be re-downloaded (see 1)
3. The user might have lots of content stored and again due to 1, those don't need to be backed up to iCloud. And really Instapaper actually has a small version of the problem. What is critical is applications that has huge amounts of data like offline maps and wikipedia. Those can be re-downloaded from their servers yet most definitely should not be backed up to iCloud due to time and cost.