Each distribution has its own /etc/fstab file. Almost all distributions come with a Documents, Music, Downloads, Pictures, Movies/Videos sub-directory in the /home partition of that distribution. If you have all these directories in a /home/user directory under a / partition and format and re-install, then yes all the data will be gone. If you want separate directories accessible from each distribution, put them on a separate partition. Create a data partition with sub-directories for Pictures, Movies, etc. You will need to do this from each distribution so that's why it would be better to familarize your self with one before doing multiple installs. You would create a data partition as root user: mkdir /mnt/data
I don't completely get it... can editing fstab give me stable direct links to that separate data partitions for default Documents, Music, Downloads, Pictures etc. folders? And if I created this data partition as a distro's home and later format that distro / partition will something happen to the separate data one?