To be very honest, I have a 3G connection with a limit of about 1.25 GB per month. Since I wanted Lion as quick as possible, I downloaded 1 GB of material using the 3G connection (took me a very, very short time - relatively). When I tried to resume the download from the App Store using my normal internet connection it didn't, and I lost about 1GB of stuff.

That's why I posted the earlier message.

In the interest of full disclosure, it was probably because the Mac App Store needed to re-authenticate me (I changed IPs remember), clicking resume resulted in me not being able to start the download, and the App Store just decided that the 1GB downloaded was useless.

The point about flaky internet connections, and "chunk"ed downloads still stands. I don't expect to be able to get through this download, and even my current issue would have been more gracefully handled with a smaller download size since only 1 chunk of data would have been lost.

Note: Interestingly, my 3G connection is more reliable than my broadband with respect to reliability. Even more interestingly, the provider is the same in both cases.