Thanks for those, some are great.

This is my list, more "sysadmin"-ey:

http://www.reddit.com/r/BSD/

http://www.reddit.com/r/cableporn/

http://www.reddit.com/r/DataHoarder/

http://www.reddit.com/r/devkit/

http://www.reddit.com/r/ECE/

http://www.reddit.com/r/embeddedlinux/

http://www.reddit.com/r/freebsd/

http://www.reddit.com/r/haikuOS/

http://www.reddit.com/r/homelab/

http://www.reddit.com/r/HomeNetworking/

http://www.reddit.com/r/HomeServer/

http://www.reddit.com/r/kernel/

http://www.reddit.com/r/linux/

http://www.reddit.com/r/linuxadmin/

http://www.reddit.com/r/linuxdev/

http://www.reddit.com/r/linux_devices/

http://www.reddit.com/r/NetBSD/

http://www.reddit.com/r/netsec/

http://www.reddit.com/r/netsecstudents/

http://www.reddit.com/r/networking/

http://www.reddit.com/r/openbsd/

http://www.reddit.com/r/opensourcehardware/

http://www.reddit.com/r/openSUSE/

http://www.reddit.com/r/openwrt/

http://www.reddit.com/r/osdev/

http://www.reddit.com/r/RTLSDR/

http://www.reddit.com/r/sysadmin/

http://www.reddit.com/r/systems/

http://www.reddit.com/r/unix/

http://www.reddit.com/r/usefulscripts/