From my contributions, you can see I am pretty interested in:
- disk encryption and security/cryptography in general
- filesystems and storage, most notably LVM and ext4
- SSD optimizations like discard/TRIM.
/bootencryption is now possible for machines you locally access if you use GRUB
- encrypt your servers/headless machines too: you can remotely unlock them via SSH!
- LVM: how to resize logical volumes and their filesytems in one step
- ext4's bytes-per-inode ratio helps saving space on large file systems
- TRIM: stop using the discard mount option!!