tmpfs isn't swap space, it's just a file system that stays in virtual memory (which may include swap space if your system has any available).
It's used anywhere where the system needs to store small files that are only relevant whilst the system is running, and can be safely lost on a crash or reboot. Indeed, in some cases having left-over files from a previous boot may cause problems.
"mount | grep tmpfs" on my F16 gives:
devtmpfs on /dev type devtmpfs (rw,nosuid,relatime,seclabel,size=2009612k,nr_inodes=502403,mode=755)
tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev,relatime,seclabel)
tmpfs on /run type tmpfs (rw,nosuid,nodev,relatime,seclabel,mode=755)
tmpfs on /sys/fs/cgroup type tmpfs (rw,nosuid,nodev,noexec,relatime,seclabel,mode=755)
tmpfs on /media type tmpfs (rw,nosuid,nodev,noexec,relatime,rootcontext=system_u:object_r:mnt_t:s0,seclabel,mode=755)
/dev contains device files which are created and removed automatically by the udev daemon, as hardware is added or removed etc. (devtmps is just a tmpfs that was created specially by the kernel early in the boot process, which contains the core devices pre-created so that the boot process has something to work with before udevd is loaded.)
/dev/shm is used by the POSIX shared memory facilities.
/run contains resource locks and PID files etc. which are relevant to currently-running daemons. /var/run and /var/lock are symlinks back to /run for compatibility reasons.
/media contains the mount-points of removable media (e.g. optical discs and USB drives), which are created and removed automatically.
/sys/fs/cgroup contains details for the cgroup system, which is used (mainly by systemd) to divide processes into groups for resource sharing etc.