Contig is a single-file defragmenter that attempts to make files contiguous on disk. Its perfect for quickly optimizing files that are continuously becoming fragmented, or that you want to ensure are in as few fragments as possible.
This was perfect for me as I wanted to make sure my vpc images are stored on the disk as a single file. I also noticed that my page file was slightly fragmented. Incidentally he’s also written some other cool utilities like a page file defragmenter which is extremely useful. Another quick search on Page file optimization provided a useful article.