[estumpges]

I don't know how hard this would be, but it would be great if software update would allow you to check for updates on all software installed on your computer instead of just Apple software. Of course sofware writters would have to update their sofware to allow Leopard to do this but it would make life a whole lot easier for users. Would this be possible?

[d00d]

There is no technical reason. However, there are administrative barriers to this. The first is that Apple would need to police the updates to make sure someone doesn't slip malware in through the update mechanism. Now, even if you could trust the developers, there's still the possibility of an authors credentials and website being compromised and replaced with malware. That means that Apple would have to check each and every update. That's a monumental task and I doubt we'll see anytime soon.