Copy metadata with files to new site collections
Why does it seem impossible (without serious custom work) to copy a file from one site collection to another and have it retain its metadata?
Scott Brickey commented
i believe (though haven't confirmed) that if you have syndicated content types, and use the SendTo feature to copy the file to the other location... that it will retain its metadata.
if you're doing things like downloading the file, or using Windows Explorer (via WebDAV), then there's no chance... no part of a .TXT file supports metadata, so there's nowhere to store the info when you download it, so there's no metadata when you upload it to its new location.