Comment by pifm_guy

If you look at the on-disk structure of NTFS, you see that it's design is rather similar to databases. Metadata and file data are treated in the same way. Every 'special' data structure, like for example the record of which disk blocks are free, is actually stored as a [hidden] file.

If a file is short, the data doesn't need a whole disk block allocated to it. Likewise, if a file name is really long, that string doesn't need to be stored together with other metadata.