The ntfs-3g FUSE driver (almost certainly the one you're using if you've got read/write) talks ADS, but not by default (except on Linux apparently, where ADS are mapped to extended attributes by default).
From ntfs-3g's man page:
Alternate Data Streams (ADS)
NTFS stores all data in streams. Every
file has exactly one unnamed data
stream and can have many named data
streams. The size of a file is the
size of its unnamed data stream. By
default, ntfs-3g will only read the
unnamed data stream.
By using the
you will be able to read any named
data streams, simply by specifying the
stream's name after a colon. For
Named data streams act like normal
files, so you can read from them,
write to them and even delete them
(using rm). You can list all the named
data streams a file has by getting the
As for the flip-side of your question, the basic umbrella term for this extra metadata would be extended file attributes. The various unices and their filesystems have support for this kind of thing under various names: the ext* family and many other Linux fs's call these xattrs.