Warez cut into 1.44 meg chunks to fit conveniently on 3½" floppy disks and account for poor modem speeds. This format was popular in the BBS days when floppies were still a useful storage medium and 28.8 was blazing fast. The floppy warez style became unpopular when gamez and appz started spanning more than 47 disks.

These are some programs used to span disks:
PKZIP.EXE -ex -&fv