SunOS 5.x is delivered with the "automounter" enabled. The automounter is designed for NFS sites, to simplify maintenance of the list of filesystems that need mounting. However it is a burden for standalone sites.
The automounter takes over /home and in effect becomes the NFS server for it, so it no longer behaves like a normal directory. This is normally a Good Thing as it simplifies administration if everybody's home directory is /home/<username>, regardless of their physical location.
If you want to continue to use the automounter, edit /etc/auto_master and comment out the line starting with "/home". Then run the "automount" command which will cause automountd to reload the maps.
To kill it off for standalone or small networks running Solaris 2.3 or later, you can stop automountd by running "/etc/init.d/autofs stop". Prevent it from starting at boot time by renaming the file /etc/rc2.d/SXXautofs to /etc/rc2.d/sXXautofs, where XX are two digits depending on the OS release. (If you change your mind, just rename it back)
In Solaris 2.2, the procedure is different. You need to comment out the three lines in /etc/init.d/nfs.client that start "if" (from the if to the fi!!), and reboot (Solaris 2.2)
To learn about it, read the O'Reilly book "Managing NFS and NIS", or ftp the white paper 'The Art of Automounting". from sunsite.unc.edu in the directory /pub/sun-info/white-papers.