SizeMe scans a selected directory for the size of each item. Then it compares that to the given media size, and gives you a list over how many items you need. Each item will contain how many percent a item takes. When you want to copy/move/burn you can drag'n'drop the items into any given place. If you want to burning your "My documents" folder you might select CD (700MB) and then it will create several discs as close to 100% full.