Maybe less of a hint, and more of a “I didn’t know you could do that!”

If you have connected to a remote Mac using Screen Sharing and don’t have a mounted disk, then you can still copy between the two Macs via drag and drop.

Basically, you take a file from the local Finder and drag it to a window of the remote Finder. This will automatically initiate a copy. The reverse is also true. A little experimenting shows numerous applications can act as source, but in all cases a Finder window needs to be the final destination.

[crarko adds: I’ve done this for ages using things other than Apple’s built-in Screen Sharing program, so I don’t know when this became available. Did it come along with AirDrop? The full Remote Desktop program has done this since the beginning.]

Source: Mac OSX Hints